1
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Brandt PC, Provornikova E, Bale SD, Cocoros A, DeMajistre R, Dialynas K, Elliott HA, Eriksson S, Fields B, Galli A, Hill ME, Horanyi M, Horbury T, Hunziker S, Kollmann P, Kinnison J, Fountain G, Krimigis SM, Kurth WS, Linsky J, Lisse CM, Mandt KE, Magnes W, McNutt RL, Miller J, Moebius E, Mostafavi P, Opher M, Paxton L, Plaschke F, Poppe AR, Roelof EC, Runyon K, Redfield S, Schwadron N, Sterken V, Swaczyna P, Szalay J, Turner D, Vannier H, Wimmer-Schweingruber R, Wurz P, Zirnstein EJ. Future Exploration of the Outer Heliosphere and Very Local Interstellar Medium by Interstellar Probe. SPACE SCIENCE REVIEWS 2023; 219:18. [PMID: 36874191 PMCID: PMC9974711 DOI: 10.1007/s11214-022-00943-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 12/07/2022] [Indexed: 06/18/2023]
Abstract
A detailed overview of the knowledge gaps in our understanding of the heliospheric interaction with the largely unexplored Very Local Interstellar Medium (VLISM) are provided along with predictions of with the scientific discoveries that await. The new measurements required to make progress in this expanding frontier of space physics are discussed and include in-situ plasma and pick-up ion measurements throughout the heliosheath, direct sampling of the VLISM properties such as elemental and isotopic composition, densities, flows, and temperatures of neutral gas, dust and plasma, and remote energetic neutral atom (ENA) and Lyman-alpha (LYA) imaging from vantage points that can uniquely discern the heliospheric shape and bring new information on the interaction with interstellar hydrogen. The implementation of a pragmatic Interstellar Probe mission with a nominal design life to reach 375 Astronomical Units (au) with likely operation out to 550 au are reported as a result of a 4-year NASA funded mission study.
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Affiliation(s)
- P. C. Brandt
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - E. Provornikova
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - S. D. Bale
- University of California Berkeley, Berkeley, CA USA
| | - A. Cocoros
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - R. DeMajistre
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - K. Dialynas
- Office of Space Research and Technology, Academy of Athens, Athens, 10679 Greece
| | | | - S. Eriksson
- Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO USA
| | - B. Fields
- University of Illinois Urbana-Champaign, Urbana, IL USA
| | - A. Galli
- University of Bern, Bern, Switzerland
| | - M. E. Hill
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - M. Horanyi
- Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, Boulder, CO USA
| | | | | | - P. Kollmann
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - J. Kinnison
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - G. Fountain
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - S. M. Krimigis
- Office of Space Research and Technology, Academy of Athens, Athens, 10679 Greece
| | | | - J. Linsky
- University of Colorado Boulder, Boulder, CO USA
| | - C. M. Lisse
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - K. E. Mandt
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - W. Magnes
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - R. L. McNutt
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | | | - E. Moebius
- University of New Hampshire, Durham, NH USA
| | - P. Mostafavi
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - M. Opher
- Boston University, Boston, MA USA
| | - L. Paxton
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - F. Plaschke
- Technical University Braunschweig, Braunschweig, Germany
| | - A. R. Poppe
- University of California Berkeley, Berkeley, CA USA
| | - E. C. Roelof
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | - K. Runyon
- Planetary Science Institute, Tucson, AZ USA
| | | | | | | | | | - J. Szalay
- Princeton University, Princeton, NJ USA
| | - D. Turner
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD USA
| | | | | | - P. Wurz
- University of Bern, Bern, Switzerland
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Zirnstein EJ, Shrestha BL, McComas DJ, Dayeh MA, Heerikhuisen J, Reisenfeld DB, Sokół JM, Swaczyna P. Oblique and rippled heliosphere structures from the Interstellar Boundary Explorer. NATURE ASTRONOMY 2022; 6:1398-1413. [PMID: 36531130 PMCID: PMC9744672 DOI: 10.1038/s41550-022-01798-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 08/26/2022] [Indexed: 06/17/2023]
Abstract
Past analysis has shown that the heliosphere structure can be deduced from correlations between long-scale solar wind pressure evolution and energetic neutral atom emissions. However, this required spatial and temporal averaging that smoothed out small or dynamic features of the heliosphere. In late 2014, the solar wind dynamic pressure increased by roughly 50% over a period of 6 months, causing a time and directional-dependent rise in around 2-6 keV energetic neutral atom fluxes from the heliosphere observed by the Interstellar Boundary Explorer. Here, we use the 2014 pressure enhancement to provide a simultaneous derivation of the three-dimensional heliospheric termination shock (HTS) and heliopause (HP) distances at high resolution from Interstellar Boundary Explorer measurements. The analysis reveals rippled HTS and HP surfaces that are oblique with respect to the local interstellar medium upwind direction, with significant asymmetries in the heliosphere structure compared to steady-state heliosphere models. We estimate that the heliosphere boundaries contain roughly ten astronomical unit-sized spatial variations, with slightly larger variations on the HTS surface than the HP and a large-scale, southwards-directed obliquity of the surfaces in the meridional plane. Comparisons of the derived HTS and HP distances with Voyager observations indicate substantial differences in the heliosphere boundaries in the northern versus southern hemispheres and their motion over time.
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Affiliation(s)
- Eric J. Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ USA
| | - Bishwas L. Shrestha
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ USA
| | - David J. McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ USA
| | - Maher A. Dayeh
- Southwest Research Institute, San Antonio, TX USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX USA
| | - Jacob Heerikhuisen
- Department of Mathematics and Statistics, University of Waikato, Hamilton, New Zealand
| | | | | | - Paweł Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ USA
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3
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Wang BB, Bi XJ, Fang K, Lin SJ, Yin PF. Solar modulation of cosmic proton and helium with AMS-02. Int J Clin Exp Med 2022. [DOI: 10.1103/physrevd.106.063006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Rankin JS, Bindi V, Bykov AM, Cummings AC, Della Torre S, Florinski V, Heber B, Potgieter MS, Stone EC, Zhang M. Galactic Cosmic Rays Throughout the Heliosphere and in the Very Local Interstellar Medium. SPACE SCIENCE REVIEWS 2022; 218:42. [PMID: 35855211 PMCID: PMC9287243 DOI: 10.1007/s11214-022-00912-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
We review recent observations and modeling developments on the subject of galactic cosmic rays through the heliosphere and in the Very Local Interstellar Medium, emphasizing knowledge that has accumulated over the past decade. We begin by highlighting key measurements of cosmic-ray spectra by Voyager, PAMELA, and AMS and discuss advances in global models of solar modulation. Next, we survey recent works related to large-scale, long-term spatial and temporal variations of cosmic rays in different regimes of the solar wind. Then we highlight new discoveries from beyond the heliopause and link these to the short-term evolution of transients caused by solar activity. Lastly, we visit new results that yield interesting insights from a broader astrophysical perspective.
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Affiliation(s)
- Jamie S. Rankin
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 USA
| | - Veronica Bindi
- Physics and Astronomy Department, University of Hawaii, Honolulu, HI 96822 USA
| | | | | | | | - Vladimir Florinski
- Center for Space Plasma and Aeronomic Research (CSPAR) and Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | - Bernd Heber
- Institute for Experimental and Applied Physics, Christian Albrechts University in Kiel, Kiel, Germany
| | - Marius S. Potgieter
- Institute for Experimental and Applied Physics, Christian Albrechts University in Kiel, Kiel, Germany
| | | | - Ming Zhang
- Department of Physics and Space Sciences, Florida Institute of Technology, Melbourn, FL 32901 USA
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5
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The March 2012 Heat Wave in Northeast America as a Possible Effect of Strong Solar Activity and Unusual Space Plasma Interactions. ATMOSPHERE 2022. [DOI: 10.3390/atmos13060926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the past two decades, the world has experienced an unprecedented number of extreme weather events, some causing major human suffering and economic damage. The March 2012 heat wave is one of the most known and broadly discussed events in the Northeast United States (NE-USA). The present study examines in depth the possible influence of solar activity on the historic March 2012 heat wave based on a comparison of solar/space and meteorological data. Our research suggests that the historic March 2012 heat wave (M2012HW) and the March 1910 heat wave (M1910HW), which occurred a century earlier in NE-USA, were related to Sun-generated special space plasma structures triggering large magnetic storms. Furthermore, the largest (Dst = −222 nT) magnetic storm during solar cycle 24 in March 2015 (only three years later than the March 2012 events) occurred in relation to another heat wave (M2015HW) in NE-USA. Both these heat waves, M2012HW and M2015HW, resemble each other in many ways: they were characterized by extremely huge temperature increases ΔΤΜ = 30° and 32° (with maximum temperatures ΤΜ = 28° and 23°, respectively) during a positive North Atlantic Oscillation index, the high temperatures coincided with large-scale warm air streaming from southern latitudes, they were accompanied by superstorms caused by unexpected geoeffective interplanetary coronal mass ejections (ICMEs), and the ICME-related solar energetic particle (SEP) events were characterized by a proton spectrum extending to very high (>0.5 GeV) energies. We infer that (i) all three heat waves examined (M2012HW, M2015HW, M1910HW) were related with strong magnetic storms triggered by effective solar wind plasma structures, and (b) the heat wave in March 2012 and the related solar activity was not an accidental coincidence; that is, the M2012HW was most probably affected by solar activity. Future case and statistical studies are needed to further check the hypothesis put forward here, which might improve atmospheric models in helping people’s safety, health and life.
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Richardson JD, Burlaga LF, Elliott H, Kurth WS, Liu YD, von Steiger R. Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium. SPACE SCIENCE REVIEWS 2022; 218:35. [PMID: 35664862 DOI: 10.1007/s11214-006-9023-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/14/2022] [Indexed: 05/23/2023]
Abstract
The Voyager spacecraft have left the heliosphere and entered the interstellar medium, making the first observations of the termination shock, heliosheath, and heliopause. New Horizons is observing the solar wind in the outer heliosphere and making the first direct observations of solar wind pickup ions. This paper reviews the observations of the solar wind plasma and magnetic fields throughout the heliosphere and in the interstellar medium.
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Affiliation(s)
- J D Richardson
- Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - L F Burlaga
- NASA Goddard Space Flight Center, Code 673, Greenbelt, MD 20771 USA
| | - H Elliott
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 USA
| | - W S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Y D Liu
- State Key Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - R von Steiger
- Universität Bern, Bern, 2 Switzerland
- International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland
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Richardson JD, Burlaga LF, Elliott H, Kurth WS, Liu YD, von Steiger R. Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium. SPACE SCIENCE REVIEWS 2022; 218:35. [PMID: 35664862 DOI: 10.1007/s11214-011-9825-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/14/2022] [Indexed: 05/23/2023]
Abstract
The Voyager spacecraft have left the heliosphere and entered the interstellar medium, making the first observations of the termination shock, heliosheath, and heliopause. New Horizons is observing the solar wind in the outer heliosphere and making the first direct observations of solar wind pickup ions. This paper reviews the observations of the solar wind plasma and magnetic fields throughout the heliosphere and in the interstellar medium.
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Affiliation(s)
- J D Richardson
- Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - L F Burlaga
- NASA Goddard Space Flight Center, Code 673, Greenbelt, MD 20771 USA
| | - H Elliott
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 USA
| | - W S Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Y D Liu
- State Key Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - R von Steiger
- Universität Bern, Bern, 2 Switzerland
- International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland
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8
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Richardson JD, Burlaga LF, Elliott H, Kurth WS, Liu YD, von Steiger R. Observations of the Outer Heliosphere, Heliosheath, and Interstellar Medium. SPACE SCIENCE REVIEWS 2022; 218:35. [PMID: 35664862 PMCID: PMC9156517 DOI: 10.1007/s11214-022-00899-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/14/2022] [Indexed: 05/08/2023]
Abstract
The Voyager spacecraft have left the heliosphere and entered the interstellar medium, making the first observations of the termination shock, heliosheath, and heliopause. New Horizons is observing the solar wind in the outer heliosphere and making the first direct observations of solar wind pickup ions. This paper reviews the observations of the solar wind plasma and magnetic fields throughout the heliosphere and in the interstellar medium.
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Affiliation(s)
- J. D. Richardson
- Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - L. F. Burlaga
- NASA Goddard Space Flight Center, Code 673, Greenbelt, MD 20771 USA
| | - H. Elliott
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 USA
| | - W. S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - Y. D. Liu
- State Key Laboratory for Space Weather, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - R. von Steiger
- Universität Bern, Bern, 2 Switzerland
- International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland
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Zank GP, Sterken V, Giacalone J, Möbius E, von Steiger R, Stone ES, Krimigis SM, Richardson JD, Linsky J, Izmodenov V, Heber B. The Early History of Heliospheric Science and the Spacecraft That Made It Possible. SPACE SCIENCE REVIEWS 2022; 218:34. [PMID: 35645425 PMCID: PMC9132875 DOI: 10.1007/s11214-022-00900-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 05/02/2022] [Indexed: 06/15/2023]
Abstract
Our understanding of the interaction of the large-scale heliosphere with the local interstellar medium (LISM) has undergone a profound change since the very earliest analyses of the problem. In part, the revisions have been a consequence of ever-improving and widening observational results, especially those that identified the entrance of interstellar material and gas into the heliosphere. Accompanying these observations was the identification of the basic underlying physics of how neutral interstellar gas and interstellar charged particles of different energies, up to and including interstellar dust grains, interacted with the temporal flows and electromagnetic fields of the heliosphere. The incorporation of these various basic effects into global models of the interaction, whether focused on neutral interstellar gas and pickup ions, energetic particles such as anomalous and galactic cosmic rays, or magnetic fields and large-scale flows, has profoundly changed our view of how the heliosphere and LISM interact. This article presents a brief history of the conceptual and observation evolution of our understanding of the interaction of the heliosphere with the local interstellar medium, up until approximately 1996.
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Affiliation(s)
- G. P. Zank
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 USA
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | | | - J. Giacalone
- Department of Planetary Science, University of Arizona, Tucson, USA
| | - E. Möbius
- University of New Hampshire, Durham, USA
| | - R. von Steiger
- International Space Science Institute, Bern, Switzerland
| | - E. S. Stone
- California Institute of Technology, Pasadena, USA
| | - S. M. Krimigis
- Applied Physics Laboratory, Johns Hopkins University, Baltimore, USA
| | - J. D. Richardson
- Kavli Center for Astrophysics and Space Science, Massachusetts Institute of Technology, Cambridge, USA
| | - J. Linsky
- JILA, University of Colorado and NIST, Boulder, CO 80309 USA
| | - V. Izmodenov
- Center for Fundamental and Applied Mathematics, Lomonosov Moscow State University, Moscow, Russia
- Space Research Institute (IKI) Russian Academy of Sciences, Moscow, Russia
| | - B. Heber
- University of Kiel, Kiel, Germany
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The Solar-Electric Sail: Application to Interstellar Migration and Consequences for SETI. UNIVERSE 2022. [DOI: 10.3390/universe8050252] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Solar-Electric Sail accelerates by reflecting positively charged solar wind ions. If it is used to propel an interstellar migration mission, its interstellar cruise velocity relative to the home star cannot exceed the solar wind velocity. In an effort to analytically determine interstellar cruise velocity for a 107 kg generation ship, a constant solar wind velocity within the heliosphere of a Sun-like star of 600 km/s is assumed. The solar wind proton density at 1 AU is also considered constant at 10 protons per cubic centimeter. Solar wind density is assumed to decrease with the inverse square of solar distance. It is shown that, to maintain sufficient acceleration to achieve an interstellar cruise velocity about 70% of the solar wind velocity, the radius of the sail’s electric field is enormous—greater than 105 km. Because the solar wind velocity and density are not constant, field strength must be varied rapidly to compensate for solar wind variation. Although not competitive with the ultimate theoretical performance of solar-photon sail propelled migrations departing from Sun-like stars, the solar-electric sail might be superior in this application for migration from dim K and M main sequence stars. Such migrations conducted during close stellar encounters might have durations < 1000 terrestrial years. If only a tiny fraction of M dwarf stars host star-faring civilizations, a significant fraction of Milky Way galaxy planetary systems may have been inhabited, even if no major advances over currently postulated interstellar transportation systems are postulated. SETI theoreticians should consider this when estimating the effects of interstellar colonization.
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Galli A, Baliukin II, Bzowski M, Izmodenov VV, Kornbleuth M, Kucharek H, Möbius E, Opher M, Reisenfeld D, Schwadron NA, Swaczyna P. The Heliosphere and Local Interstellar Medium from Neutral Atom Observations at Energies Below 10 keV. SPACE SCIENCE REVIEWS 2022; 218:31. [PMID: 35673597 PMCID: PMC9165285 DOI: 10.1007/s11214-022-00901-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 05/05/2022] [Indexed: 05/08/2023]
Abstract
As the heliosphere moves through the surrounding interstellar medium, a fraction of the interstellar neutral helium, hydrogen, and heavier species crossing the heliopause make it to the inner heliosphere as neutral atoms with energies ranging from few eV to several hundred eV. In addition, energetic neutral hydrogen atoms originating from solar wind protons and from pick-up ions are created through charge-exchange with interstellar atoms. This review summarizes all observations of heliospheric energetic neutral atoms and interstellar neutrals at energies below 10 keV. Most of these data were acquired with the Interstellar Boundary Explorer launched in 2008. Among many other IBEX breakthroughs, it provided the first ever all-sky maps of energetic neutral atoms from the heliosphere and enabled the science community to measure in-situ interstellar neutral hydrogen, oxygen, and neon for the first time. These observations have revolutionized and keep challenging our understanding of the heliosphere shaped by the combined forces of the local interstellar flow, the local interstellar magnetic field, and the time-dependent solar wind.
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Affiliation(s)
- André Galli
- Physics Institute, University of Bern, Bern, Switzerland
| | - Igor I. Baliukin
- Space Research Institute of Russian Academy of Sciences, Moscow, Russia
- Moscow Center for Fundamental and Applied Mathematics, Lomonosov Moscow State University, Moscow, Russia
| | - Maciej Bzowski
- Space Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - Vladislav V. Izmodenov
- Space Research Institute of Russian Academy of Sciences, Moscow, Russia
- Moscow Center for Fundamental and Applied Mathematics, Lomonosov Moscow State University, Moscow, Russia
| | | | | | | | | | | | | | - Paweł Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ USA
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12
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Mostafavi P, Burlaga LF, Cairns IH, Fuselier SA, Fraternale F, Gurnett DA, Kim TK, Kurth WS, Pogorelov NV, Provornikova E, Richardson JD, Turner DL, Zank GP. Shocks in the Very Local Interstellar Medium. SPACE SCIENCE REVIEWS 2022; 218:27. [PMID: 35574274 PMCID: PMC9085707 DOI: 10.1007/s11214-022-00893-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Accepted: 04/15/2022] [Indexed: 05/08/2023]
Abstract
Large-scale disturbances generated by the Sun's dynamics first propagate through the heliosphere, influence the heliosphere's outer boundaries, and then traverse and modify the very local interstellar medium (VLISM). The existence of shocks in the VLISM was initially suggested by Voyager observations of the 2-3 kHz radio emissions in the heliosphere. A couple of decades later, both Voyagers crossed the definitive edge of our heliosphere and became the first ever spacecraft to sample interstellar space. Since Voyager 1's entrance into the VLISM, it sampled electron plasma oscillation events that indirectly measure the medium's density, increasing as it moves further away from the heliopause. Some of the observed electron oscillation events in the VLISM were associated with the local heliospheric shock waves. The observed VLISM shocks were very different than heliospheric shocks. They were very weak and broad, and the usual dissipation via wave-particle interactions could not explain their structure. Estimates of the dissipation associated with the collisionality show that collisions can determine the VLISM shock structure. According to theory and models, the existence of a bow shock or wave in front of our heliosphere is still an open question as there are no direct observations yet. This paper reviews the outstanding observations recently made by the Voyager 1 and 2 spacecraft, and our current understanding of the properties of shocks/waves in the VLISM. We present some of the most exciting open questions related to the VLISM and shock waves that should be addressed in the future.
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Affiliation(s)
- P. Mostafavi
- Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723 USA
| | - L. F. Burlaga
- NASA Goddard Space Flight Center, Code 673, Greenbelt, MD 20771 USA
| | - I. H. Cairns
- School of Physics, University of Sydney, Sydney, NSW 2006 Australia
| | - S. A. Fuselier
- Southwest Research Institute, P.O. Drawer 28510, San Antonio, TX 78228 USA
- Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX 78249 USA
| | - F. Fraternale
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | - D. A. Gurnett
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - T. K. Kim
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | - W. S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 USA
| | - N. V. Pogorelov
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 USA
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35805 USA
| | - E. Provornikova
- Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723 USA
| | - J. D. Richardson
- Kavli Institute for Astrophysics and Space Research, Cambridge, MA USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - D. L. Turner
- Johns Hopkins Applied Physics Laboratory, Laurel, MD 20723 USA
| | - G. P. Zank
- Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35805 USA
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35805 USA
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13
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Koch Ocker S, Cordes JM, Chatterjee S, Gurnett DA, Kurth WS, Spangler SR. Persistent plasma waves in interstellar space detected by Voyager 1. NATURE ASTRONOMY 2021; 5:761-765. [PMID: 35005245 PMCID: PMC8740711 DOI: 10.1038/s41550-021-01363-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/30/2021] [Indexed: 05/23/2023]
Abstract
In 2012, Voyager 1 became the first in situ probe of the very local interstellar medium1. The Voyager 1 Plasma Wave System has given point estimates of the plasma density spanning about 30 au of interstellar space, revealing a large-scale density gradient2,3 and turbulence4 outside the heliopause. Previous studies of the plasma density relied on the detection of discrete plasma oscillation events triggered ahead of shocks propagating outwards from the Sun and used to infer the plasma frequency and hence density5,6. We present the detection of a class of very weak, narrowband plasma wave emission in the Voyager 1 data that persists from 2017 onwards and enables the first steadily sampled measurement of the interstellar plasma density over about 10 au with an average sampling distance of 0.03 au. We find au-scale density fluctuations that trace interstellar turbulence between episodes of previously detected plasma oscillations. Possible mechanisms for the narrowband emission include thermally excited plasma oscillations and quasi-thermal noise, and could be clarified by new findings from Voyager or a future interstellar mission. The emission's persistence suggests that Voyager 1 may be able to continue tracking the interstellar plasma density in the absence of shock-generated plasma oscillation events.
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Affiliation(s)
- Stella Koch Ocker
- Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14850, USA
| | - James M. Cordes
- Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14850, USA
| | - Shami Chatterjee
- Department of Astronomy and Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY 14850, USA
| | - Donald A. Gurnett
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
| | - William S. Kurth
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
| | - Steven R. Spangler
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242, USA
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Verscharen D, Wicks RT, Alexandrova O, Bruno R, Burgess D, Chen CHK, D’Amicis R, De Keyser J, de Wit TD, Franci L, He J, Henri P, Kasahara S, Khotyaintsev Y, Klein KG, Lavraud B, Maruca BA, Maksimovic M, Plaschke F, Poedts S, Reynolds CS, Roberts O, Sahraoui F, Saito S, Salem CS, Saur J, Servidio S, Stawarz JE, Štverák Š, Told D. A Case for Electron-Astrophysics. EXPERIMENTAL ASTRONOMY 2021; 54:473-519. [PMID: 36915623 PMCID: PMC9998602 DOI: 10.1007/s10686-021-09761-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 05/07/2021] [Indexed: 06/18/2023]
Abstract
The smallest characteristic scales, at which electron dynamics determines the plasma behaviour, are the next frontier in space and astrophysical plasma research. The analysis of astrophysical processes at these scales lies at the heart of the research theme of electron-astrophysics. Electron scales are the ultimate bottleneck for dissipation of plasma turbulence, which is a fundamental process not understood in the electron-kinetic regime. In addition, plasma electrons often play an important role for the spatial transfer of thermal energy due to the high heat flux associated with their velocity distribution. The regulation of this electron heat flux is likewise not understood. By focussing on these and other fundamental electron processes, the research theme of electron-astrophysics links outstanding science questions of great importance to the fields of space physics, astrophysics, and laboratory plasma physics. In this White Paper, submitted to ESA in response to the Voyage 2050 call, we review a selection of these outstanding questions, discuss their importance, and present a roadmap for answering them through novel space-mission concepts.
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Affiliation(s)
- Daniel Verscharen
- Mullard Space Science Laboratory, University College London, Dorking, UK
- Space Science Center, University of New Hampshire, Durham, NH USA
| | - Robert T. Wicks
- Mullard Space Science Laboratory, University College London, Dorking, UK
- Department of Mathematics, Physics and Electrical Engineering, Northumbria University, Newcastle-upon-Tyne, UK
| | - Olga Alexandrova
- Laboratoire d’Études Spatiales et d’Instrumentation en Astrophysique, Observatoire de Paris-Meudon, Paris, France
| | - Roberto Bruno
- Instituto di Astrofisica e Planetologia Spaziali, INAF, Rome, Italy
| | - David Burgess
- School of Physics and Astronomy, Queen Mary University of London, London, UK
| | | | | | - Johan De Keyser
- Royal Belgian Institute for Space Aeronomy, Brussels, Belgium
| | - Thierry Dudok de Wit
- Laboratoire de Physique et Chimie de l’Environment et de l’Espace, CNRS, University of Orléans and CNES, Orléans, France
| | - Luca Franci
- School of Physics and Astronomy, Queen Mary University of London, London, UK
- Osservatorio Astrofisico di Arcetri, INAF, Firenze, Italy
| | - Jiansen He
- School of Earth and Space Sciences, Peking University, Beijing, China
| | - Pierre Henri
- Laboratoire de Physique et Chimie de l’Environment et de l’Espace, CNRS, University of Orléans and CNES, Orléans, France
- CNRS, UCA, OCA, Lagrange, Nice, France
| | - Satoshi Kasahara
- Department of Earth and Planetary Science, University of Tokyo, Tokyo, Japan
| | | | - Kristopher G. Klein
- Lunar and Planetary Laboratory and Department of Planetary Sciences, University of Arizona, Tucson, AZ USA
| | - Benoit Lavraud
- Laboratoire d’astrophysique de Bordeaux, Université de Bordeaux, CNRS, Pessac, France
- Institut de Recherche en Astrophysique et Planétologie, CNRS, UPS, CNES, Université de Toulouse, Toulouse, France
| | - Bennett A. Maruca
- Department of Physics and Astronomy, Bartol Research Institute, University of Delaware, Newark, DE USA
| | - Milan Maksimovic
- Laboratoire d’Études Spatiales et d’Instrumentation en Astrophysique, Observatoire de Paris-Meudon, Paris, France
| | | | - Stefaan Poedts
- Centre for Mathematical Plasma Astrophysics, KU Leuven, Leuven, Belgium
- Institute of Physics, University of Maria Curie-Skłodowska, Lublin, Poland
| | | | - Owen Roberts
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - Fouad Sahraoui
- Laboratoire de Physique des Plasmas, CNRS, École Polytechnique, Sorbonne Université, Observatoire de Paris-Meudon, Paris Saclay, Palaiseau, France
| | - Shinji Saito
- Space Environment Laboratory, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Chadi S. Salem
- Space Sciences Laboratory, University of California, Berkeley, CA USA
| | - Joachim Saur
- Institut für Geophysik und Meteorologie, University of Cologne, Cologne, Germany
| | - Sergio Servidio
- Department of Physics, Università della Calabria, Rende, Italy
| | | | - Štěpán Štverák
- Astronomical Institute and Institute of Atmospheric Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - Daniel Told
- Max Planck Institute for Plasma Physics, Garching, Germany
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News Feature: Voyager still breaking barriers decades after launch. Proc Natl Acad Sci U S A 2021; 118:2106371118. [PMID: 33883284 DOI: 10.1073/pnas.2106371118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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16
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Kumar R, Sakawa Y, Sano T, Döhl LNK, Woolsey N, Morace A. Ion acceleration at two collisionless shocks in a multicomponent plasma. Phys Rev E 2021; 103:043201. [PMID: 34005941 DOI: 10.1103/physreve.103.043201] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 03/16/2021] [Indexed: 11/07/2022]
Abstract
Intense laser-plasma interactions are an essential tool for the laboratory study of ion acceleration at a collisionless shock. With two-dimensional particle-in-cell calculations of a multicomponent plasma we observe two electrostatic collisionless shocks at two distinct longitudinal positions when driven with a linearly polarized laser at normalized laser vector potential a_{0} that exceeds 10. Moreover, these shocks, associated with protons and carbon ions, show a power-law dependence on a_{0} and accelerate ions to different velocities in an expanding upstream with higher flux than in a single-component hydrogen or carbon plasma. This results from an electrostatic ion two-stream instability caused by differences in the charge-to-mass ratio of different ions. Particle acceleration in collisionless shocks in multicomponent plasma are ubiquitous in space and astrophysics, and these calculations identify the possibility for studying these complex processes in the laboratory.
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Affiliation(s)
- Rajesh Kumar
- Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Youichi Sakawa
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Takayoshi Sano
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Leonard N K Döhl
- York Plasma Institute, Department of Physics, University of York, Heslington, York YO10-5DD, United Kingdom
| | - Nigel Woolsey
- York Plasma Institute, Department of Physics, University of York, Heslington, York YO10-5DD, United Kingdom
| | - Alessio Morace
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
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Zirnstein EJ, Giacalone J, Kumar R, McComas DJ, Dayeh MA, Heerikhuisen J. Turbulence in the Local Interstellar Medium and the IBEX Ribbon. THE ASTROPHYSICAL JOURNAL 2020; 888:10.3847/1538-4357/ab594d. [PMID: 32020922 PMCID: PMC6999793 DOI: 10.3847/1538-4357/ab594d] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of turbulence in the very local interstellar medium (VLISM) have been proposed by Giacalone & Jokipii (2015) to be important in determining the structure of the Interstellar Boundary Explorer (IBEX) ribbon via particle trapping by magnetic mirroring. We further explore this effect by simulating the motion of charged particles in a turbulent magnetic field superposed on a large-scale mean field, which we consider to be either spatially-uniform or a draped field derived from a 3D MHD simulation. We find that the ribbon is not double-peaked, in contrast to Giacalone & Jokipii (2015). However, the magnetic mirror force still plays an important role in trapping particles. Furthermore, the ribbon's thickness is considerably larger if the large-scale mean field is draped around the heliosphere. Voyager 1 observations in the VLISM show a turbulent field component that is stronger than previously thought, which we test in our simulation. We find that the inclusion of turbulent fluctuations at scales ≳100 au and power consistent with Voyager 1 observations produces a ribbon whose large-scale structure is inconsistent with IBEX observations. However, restricting fluctuations to <100 au produces a smoother ribbon structure similar to IBEX observations. Different turbulence realizations produce different small-scale features (≲10°) in the ribbon, but its large-scale structure is robust if the maximum fluctuation size is ≲50 au. This suggests that the magnetic field structure at scales ≲50 au is determined by the heliosphere-VLISM interaction and cannot entirely be represented by pristine interstellar turbulence.
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Affiliation(s)
- E J Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - J Giacalone
- Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - R Kumar
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - M A Dayeh
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - J Heerikhuisen
- Department of Mathematics and Statistics, University of Waikato, Hamilton, New Zealand
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA
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18
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Zirnstein EJ, Swaczyna P, McComas DJ, Heerikhuisen J. Parallax of the IBEX Ribbon Indicates a Spatially-Retained Source. THE ASTROPHYSICAL JOURNAL 2019; 879:106. [PMID: 31395988 PMCID: PMC6687312 DOI: 10.3847/1538-4357/ab2633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In 2009, the Interstellar Boundary Explorer (IBEX) discovered the existence of a narrow "ribbon" of intense energetic neutral atom (ENA) emission projecting approximately a circle in the sky. It is believed that the ribbon originates from outside of the heliopause in radial directions ( r ) perpendicular to the local interstellar magnetic field (ISMF), B , i.e., B∙ r = 0. Swaczyna et al. (2016a) estimated the distance to the IBEX ribbon via the parallax method comparing the ribbon position observed from the opposite sides of the Sun. They found a parallax angle of 0.41° ± 0.15°, yielding a distance of140 - 38 + 84 au to a portion of the ribbon at high ecliptic latitudes. In this study, we demonstrate how the apparent shift of the ribbon in the sky, and thus the apparent distance to the ribbon's source found via the parallax, depends on the transport effects of energetic ions outside the heliopause. We find that the apparent shift of the ribbon based on the "spatial retention" model with ion enhancement near B∙ r = 0, as proposed by Schwadron & McComas (2013), agrees with the parallax of the source region. Parallax is also accurate for a homogeneously-distributed emission source. However, if there is weak pitch angle scattering and ions propagate freely along the ISMF, the apparent shift is significantly smaller than the expected parallax because of the highly anisotropic source. In light of the results from Swaczyna et al. (2016a), our results indicate that the IBEX ribbon source is spatially confined.
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Affiliation(s)
- E J Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - P Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - J Heerikhuisen
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA
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20
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Zirnstein EJ, McComas DJ, Schwadron NA, Dayeh MA, Heerikhuisen J, Swaczyna P. Strong Scattering of ~keV Pickup Ions in the Local Interstellar Magnetic Field Draped Around Our Heliosphere: Implications for the IBEX Ribbon's Source and IMAP. THE ASTROPHYSICAL JOURNAL 2019; 876:10.3847/1538-4357/ab15d6. [PMID: 31359881 PMCID: PMC6662649 DOI: 10.3847/1538-4357/ab15d6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The leading hypothesis for the origin of the Interstellar Boundary Explorer (IBEX) "ribbon" of enhanced energetic neutral atoms (ENAs) from the outer heliosphere is the secondary ENA mechanism, whereby neutralized solar wind ions escape the heliosphere and, after several charge-exchange processes, may propagate back toward Earth primarily in directions perpendicular to the local interstellar magnetic field (ISMF). However, the physical processes governing the parent protons outside of the heliopause are still unconstrained. In this study, we compute the "spatial retention" model proposed by Schwadron & McComas (2013) in a 3D simulated heliosphere. In their model, pickup ions outside the heliopause that originate from the neutral solar wind are spatially-retained in a region of space via strong pitch angle scattering before becoming ENAs. We find that the ribbon's intensity and shape can vary greatly depending on the pitch angle scattering rate both inside and outside the spatial retention region, potentially contributing to the globally distributed flux. The draping of the ISMF around the heliopause creates an asymmetry in the average distance to the ribbon's source as well as an asymmetry in the ribbon's shape, i.e., radial cross section of ENA flux through the circular ribbon. The spatial retention model adds an additional asymmetry to the ribbon's shape due to the enhancement of ions in the retention region close to the heliopause. Finally, we demonstrate how the ribbon's structure observed at 1 au is affected by different instrument capabilities, and how the Interstellar Mapping and Acceleration Probe (IMAP) may observe the ribbon.
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Affiliation(s)
- E J Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | | | - M A Dayeh
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - J Heerikhuisen
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA
| | - P Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
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21
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Zirnstein EJ, McComas DJ, Schwadron NA, Dayeh MA, Heerikhuisen J, Swaczyna P. Strong Scattering of ~keV Pickup Ions in the Local Interstellar Magnetic Field Draped Around Our Heliosphere: Implications for the IBEX Ribbon's Source and IMAP. THE ASTROPHYSICAL JOURNAL 2019; 876:247. [PMID: 31359881 DOI: 10.3847/1538-4357/ab5b91] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The leading hypothesis for the origin of the Interstellar Boundary Explorer (IBEX) "ribbon" of enhanced energetic neutral atoms (ENAs) from the outer heliosphere is the secondary ENA mechanism, whereby neutralized solar wind ions escape the heliosphere and, after several charge-exchange processes, may propagate back toward Earth primarily in directions perpendicular to the local interstellar magnetic field (ISMF). However, the physical processes governing the parent protons outside of the heliopause are still unconstrained. In this study, we compute the "spatial retention" model proposed by Schwadron & McComas (2013) in a 3D simulated heliosphere. In their model, pickup ions outside the heliopause that originate from the neutral solar wind are spatially-retained in a region of space via strong pitch angle scattering before becoming ENAs. We find that the ribbon's intensity and shape can vary greatly depending on the pitch angle scattering rate both inside and outside the spatial retention region, potentially contributing to the globally distributed flux. The draping of the ISMF around the heliopause creates an asymmetry in the average distance to the ribbon's source as well as an asymmetry in the ribbon's shape, i.e., radial cross section of ENA flux through the circular ribbon. The spatial retention model adds an additional asymmetry to the ribbon's shape due to the enhancement of ions in the retention region close to the heliopause. Finally, we demonstrate how the ribbon's structure observed at 1 au is affected by different instrument capabilities, and how the Interstellar Mapping and Acceleration Probe (IMAP) may observe the ribbon.
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Affiliation(s)
- E J Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - D J McComas
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | | | - M A Dayeh
- Southwest Research Institute, San Antonio, TX 78228, USA
| | - J Heerikhuisen
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA
| | - P Swaczyna
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
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Zirnstein EJ, Heerikhuisen J, Dayeh MA. The Role of Pickup Ion Dynamics Outside of the Heliopause in the Limit of Weak Pitch Angle Scattering: Implications for the Source of the IBEX Ribbon. THE ASTROPHYSICAL JOURNAL 2018; 855:30. [PMID: 29861499 PMCID: PMC5975221 DOI: 10.3847/1538-4357/aaaf6d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present a new model of the Interstellar Boundary Explorer (IBEX) ribbon based on the secondary energetic neutral atom (ENA) mechanism, under the assumption that there is negligible pitch angle scattering of pickup ions (PUIs) outside the heliopause. Using the results of an MHD-plasma/kinetic-neutral simulation of the heliosphere, we generate PUIs in the outer heliosheath, solve their transport using guiding center theory, and compute ribbon ENA fluxes at 1 AU. We implement several aspects of the PUI dynamics, including (1) parallel motion along the local interstellar magnetic field (ISMF), (2) advective transport with the interstellar plasma, (3) the mirror force acting on PUIs propagating along the ISMF, and (4) betatron acceleration of PUIs as they are advected within an increasing magnetic field towards the heliopause. We find that ENA fluxes at 1 AU are reduced when PUIs are allowed to move along the ISMF, and ENA fluxes are reduced even more by the inclusion of the mirror force, which pushes particles away from IBEX lines-of-sight. Inclusion of advection and betatron acceleration do not result in any significant change in the ribbon. Interestingly, the mirror force reduces the ENA fluxes from the inner edge of the ribbon more than its outer edge, effectively reducing the ribbon's width by ∼6° and increasing its radius projected on the sky. This is caused by the asymmetric draping of the ISMF around the heliopause, such that ENAs from the ribbon's inner edge originate closer to the heliopause, where the mirror force is strongest.
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Affiliation(s)
- E J Zirnstein
- Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544, USA
| | - J Heerikhuisen
- Department of Space Science, University of Alabama in Huntsville, Huntsville, AL 35899, USA
| | - M A Dayeh
- Southwest Research Institute, San Antonio, TX 78228, USA
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23
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The Origin of Compressible Magnetic Turbulence in the Very Local Interstellar Medium. ACTA ACUST UNITED AC 2017. [DOI: 10.3847/1538-4357/aa7685] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Cummings AC, Stone EC, Heikkila BC, Lal N, Webber WR, Jóhannesson G, Moskalenko IV, Orlando E, Porter TA. GALACTIC COSMIC RAYS IN THE LOCAL INTERSTELLAR MEDIUM: VOYAGER 1 OBSERVATIONS AND MODEL RESULTS. THE ASTROPHYSICAL JOURNAL 2016; 831:18. [PMID: 34646042 PMCID: PMC8507217 DOI: 10.3847/0004-637x/831/1/18] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Since 2012 August Voyager 1 has been observing the local interstellar energy spectra of Galactic cosmic-ray nuclei down to 3 MeV nuc-1 and electrons down to 2.7 MeV. The H and He spectra have the same energy dependence between 3 and 346 MeV nuc-1, with a broad maximum in the 10-50 MeV nuc-1 range and a H/He ratio of 12.2 ± 0.9. The peak H intensity is ~15 times that observed at 1 AU, and the observed local interstellar gradient of 3-346 MeV H is -0.009 ± 0.055% AU-1, consistent with models having no local interstellar gradient. The energy spectrum of electrons (e - + e +) with 2.7-74 MeV is consistent with E -1.30±0.05 and exceeds the H intensity at energies below ~50 MeV. Propagation model fits to the observed spectra indicate that the energy density of cosmic-ray nuclei with >3 MeV nuc-1 and electrons with >3 MeV is 0.83-1.02 eV cm-3 and the ionization rate of atomic H is in the range of 1.51-1.64 × 10-17 s-1. This rate is a factor >10 lower than the ionization rate in diffuse interstellar clouds, suggesting significant spatial inhomogeneity in low-energy cosmic rays or the presence of a suprathermal tail on the energy spectrum at much lower energies. The propagation model fits also provide improved estimates of the elemental abundances in the source of Galactic cosmic rays.
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Affiliation(s)
- A C Cummings
- California Institute of Technology, Pasadena, CA 91125, USA
| | - E C Stone
- California Institute of Technology, Pasadena, CA 91125, USA
| | - B C Heikkila
- Goddard Space Flight Center. Greenbelt, MD 20771, USA
| | - N Lal
- Goddard Space Flight Center. Greenbelt, MD 20771, USA
| | - W R Webber
- New Mexico State University, Las Cruces, NM 88003, USA
| | | | - I V Moskalenko
- HEPL and KIPAC, Stanford University, Stanford, CA 94305, USA
| | - E Orlando
- HEPL and KIPAC, Stanford University, Stanford, CA 94305, USA
| | - T A Porter
- HEPL and KIPAC, Stanford University, Stanford, CA 94305, USA
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Adriani O, Barbarino GC, Bazilevskaya GA, Bellotti R, Boezio M, Bogomolov EA, Bongi M, Bonvicini V, Bottai S, Bruno A, Cafagna F, Campana D, Carlson P, Casolino M, Castellini G, Donato CD, Santis CD, Simone ND, Felice VD, Formato V, Galper AM, Karelin AV, Koldashov SV, Koldobskiy S, Krutkov SY, Kvashnin AN, Leonov A, Malakhov V, Marcelli L, Martucci M, Mayorov AG, Menn W, Mergè M, Mikhailov VV, Mocchiutti E, Monaco A, Mori N, Munini R, Osteria G, Palma F, Panico B, Papini P, Pearce M, Picozza P, Ricci M, Ricciarini SB, Sarkar R, Scotti V, Simon M, Sparvoli R, Spillantini P, Stozhkov YI, Vacchi A, Vannuccini E, Vasilyev G, Voronov SA, Yurkin YT, Zampa G, Zampa N, Potgieter MS, Vos EE. TIME DEPENDENCE OF THEe−FLUX MEASURED BYPAMELADURING THE 2006 JULY–2009 DECEMBER SOLAR MINIMUM. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/0004-637x/810/2/142] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Ben-Jaffel L, Abbes I. Helium abundance in giant planets and the local interstellar medium. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1742-6596/577/1/012003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Teolis BD, Sillanpää I, Waite JH, Khurana KK. Surface current balance and thermoelectric whistler wings at airless astrophysical bodies: Cassini at Rhea. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2014; 119:8881-8901. [PMID: 26167436 PMCID: PMC4497460 DOI: 10.1002/2014ja020094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 10/02/2014] [Accepted: 10/04/2014] [Indexed: 06/04/2023]
Abstract
UNLABELLED Sharp magnetic perturbations found by the Cassini spacecraft at the edge of the Rhea flux tube are consistent with field-aligned flux tube currents. The current system results from the difference of ion and electron gyroradii and the requirement to balance currents on the sharp Rhea surface. Differential-type hybrid codes that solve for ion velocity and magnetic field have an intrinsic difficulty modeling the plasma absorber's sharp surface. We overcome this problem by instead using integral equations to solve for ion and electron currents and obtain agreement with the magnetic perturbations at Rhea's flux tube edge. An analysis of the plasma dispersion relations and Cassini data reveals that field-guided whistler waves initiated by (1) the electron velocity anisotropy in the flux tube and (2) interaction with surface sheath electrostatic waves on topographic scales may facilitate propagation of the current system to large distances from Rhea. Current systems like those at Rhea should occur generally, for plasma absorbers of any size such as spacecraft or planetary bodies, in a wide range of space plasma environments. Motion through the plasma is not essential since the current system is thermodynamic in origin, excited by heat flow into the object. The requirements are a difference of ion and electron gyroradii and a sharp surface, i.e., without a significant thick atmosphere. KEY POINTS Surface current balance condition yields a current system at astronomical bodiesCurrent system possible for sharp (airless) objects of any sizeCurrent system is thermoelectric and motion through the plasma nonessential.
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Affiliation(s)
- B D Teolis
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - I Sillanpää
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - J H Waite
- Space Science Division, Southwest Research Institute San Antonio, Texas, USA
| | - K K Khurana
- Institute of Geophysics and Planetary Physics, University of California Los Angeles, California, USA
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Gurnett DA, Kurth WS, Burlaga LF, Ness NF. In situ observations of interstellar plasma with Voyager 1. SCIENCE (NEW YORK, N.Y.) 2013; 341:1489-1492. [PMID: 24030496 DOI: 10.1088/2041-8205/778/1/l3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Launched over 35 years ago, Voyagers 1 and 2 are on an epic journey outward from the Sun to reach the boundary between the solar plasma and the much cooler interstellar medium. The boundary, called the heliopause, is expected to be marked by a large increase in plasma density, from about 0.002 per cubic centimeter (cm(-3)) in the outer heliosphere, to about 0.1 cm(-3) in the interstellar medium. On 9 April 2013, the Voyager 1 plasma wave instrument began detecting locally generated electron plasma oscillations at a frequency of about 2.6 kilohertz. This oscillation frequency corresponds to an electron density of about 0.08 cm(-3), very close to the value expected in the interstellar medium. These and other observations provide strong evidence that Voyager 1 has crossed the heliopause into the nearby interstellar plasma.
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Affiliation(s)
- D A Gurnett
- University of Iowa, Iowa City, IA 52242, USA.
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