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Elliott SS, Breneman AW, Colpitts C, Pettit JM, Cattell CA, Halford AJ, Shumko M, Sample J, Johnson AT, Miyoshi Y, Kasahara Y, Cully CM, Nakamura S, Mitani T, Hori T, Shinohara I, Shiokawa K, Matsuda S, Connors M, Ozaki M, Manninen J. Quantifying the Size and Duration of a Microburst-Producing Chorus Region on 5 December 2017. Geophys Res Lett 2022; 49:e2022GL099655. [PMID: 36247517 PMCID: PMC9540649 DOI: 10.1029/2022gl099655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/06/2022] [Accepted: 07/31/2022] [Indexed: 06/16/2023]
Abstract
Microbursts are impulsive (<1 s) injections of electrons into the atmosphere, thought to be caused by nonlinear scattering by chorus waves. Although attempts have been made to quantify their contribution to outer belt electron loss, the uncertainty in the overall size and duration of the microburst region is typically large, so that their contribution to outer belt loss is uncertain. We combine datasets that measure chorus waves (Van Allen Probes [RBSP], Arase, ground-based VLF stations) and microburst (>30 keV) precipitation (FIREBIRD II and AC6 CubeSats, POES) to determine the size of the microburst-producing chorus source region beginning on 5 December 2017. We estimate that the long-lasting (∼30 hr) microburst-producing chorus region extends from 4 to 8Δ MLT and 2-5Δ L. We conclude that microbursts likely represent a major loss source of outer radiation belt electrons for this event.
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Affiliation(s)
| | | | | | | | | | | | - M. Shumko
- NASA Goddard Space Flight CenterGreenbeltMDUSA
| | - J. Sample
- Montana State UniversityBozemanMTUSA
| | | | | | | | | | | | | | - T. Hori
- ISEENagoya UniversityNagoyaJapan
| | | | | | | | | | - M. Ozaki
- Kanazawa UniversityKanazawaJapan
| | - J. Manninen
- Sodankylä Geophysical ObservatoryUniversity of OuluSodankyläFinland
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Shumko M, Johnson AT, O'Brien TP, Turner DL, Greeley AD, Sample JG, Blake JB, Blum LW, Halford AJ. Statistical Properties of Electron Curtain Precipitation Estimated With AeroCube-6. J Geophys Res Space Phys 2020; 125:e2020JA028462. [PMID: 33520562 PMCID: PMC7816229 DOI: 10.1029/2020ja028462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/09/2020] [Accepted: 11/02/2020] [Indexed: 06/12/2023]
Abstract
Curtain precipitation is a recently discovered stationary, persistent, and latitudinally narrow electron precipitation phenomenon in low Earth orbit. Curtains are observed over consecutive passes of the dual AeroCube-6 CubeSats while their in-track lag varied from a fraction of a second to 65 s, with dosimeters that are sensitive to >35-keV electrons. This study uses the AeroCube-6 mission to quantify the statistical properties of 1,634 curtains observed over 3 years. We found that many curtains are narrower than 10 km in the latitudinal direction with 90% narrower than 20 km. We examined the geographic, magnetic local time, and geomagnetic dependence of curtains. We found that curtains are observed in the late-morning and premidnight magnetic local times, with a higher occurrence rate at premidnight, and curtains are observed more often during times of enhanced Auroral Electrojet. We found a few curtains in the bounce loss cone region above the North Atlantic, whose electrons were continuously scattered for at least 6 s. Such observations suggest that continuous curtain precipitation may be a significant loss of >35-keV electrons from the magnetosphere into the atmosphere. We hypothesize that the curtains observed in the bounce loss cone were accelerated by parallel electric fields, and we show that this mechanism is consistent with the observations.
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Affiliation(s)
- M. Shumko
- Department of PhysicsMontana State UniversityBozemanMTUSA
- NASA's Goddard Space Flight CenterGreenbeltMDUSA
| | - A. T. Johnson
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - T. P. O'Brien
- Space Science Applications LaboratoryThe Aerospace CorporationEl SegundoCAUSA
| | - D. L. Turner
- Johns Hopkins Applied Physics LaboratoryLaurelMDUSA
| | | | - J. G. Sample
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - J. B. Blake
- Space Science Applications LaboratoryThe Aerospace CorporationEl SegundoCAUSA
| | - L. W. Blum
- NASA's Goddard Space Flight CenterGreenbeltMDUSA
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Johnson AT, Shumko M, Griffith B, Klumpar DM, Sample J, Springer L, Leh N, Spence HE, Smith S, Crew A, Handley M, Mashburn KM, Larsen BA, Blake JB. The FIREBIRD-II CubeSat mission: Focused investigations of relativistic electron burst intensity, range, and dynamics. Rev Sci Instrum 2020; 91:034503. [PMID: 32260014 DOI: 10.1063/1.5137905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
FIREBIRD-II is a National Science Foundation funded CubeSat mission designed to study the scale size and energy spectrum of relativistic electron microbursts. The mission consists of two identical 1.5 U CubeSats in a low earth polar orbit, each with two solid state detectors that differ only in the size of their geometric factors and fields of view. Having two spacecraft in close orbit allows the scale size of microbursts to be investigated through the intra-spacecraft separation when microbursts are observed simultaneously on each unit. Each detector returns high cadence (10 s of ms) measurements of the electron population from 200 keV to >1 MeV across six energy channels. The energy channels were selected to fill a gap in the observations of the Heavy Ion Large Telescope instrument on the Solar, Anomalous, and Magnetospheric Particle Explorer. FIREBIRD-II has been in orbit for 5 years and continues to return high quality data. After the first month in orbit, the spacecraft had separated beyond the expected scale size of microbursts, so the focus has shifted toward conjunctions with other magnetospheric missions. FIREBIRD-II has addressed all of its primary science objectives, and its long lifetime and focus on conjunctions has enabled additional science beyond the scope of the original mission. This paper presents a brief history of the FIREBIRD mission's science goals, followed by a description of the instrument and spacecraft. The data products are then discussed along with some caveats necessary for proper use of the data.
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Affiliation(s)
- A T Johnson
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - M Shumko
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - B Griffith
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - D M Klumpar
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - J Sample
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - L Springer
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - N Leh
- Physics Department, Montana State University, Bozeman, Montana 59717, USA
| | - H E Spence
- Physics Department, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - S Smith
- Physics Department, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - A Crew
- Applied Physics Laboratory, Johns Hopkins University, Laurel, Maryland 20723, USA
| | - M Handley
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - K M Mashburn
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B A Larsen
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J B Blake
- Space Science Applications Laboratory, The Aerospace Corporation, El Segundo, California 90245, USA
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Shumko M, Johnson AT, Sample JG, Griffith BA, Turner DL, O'Brien TP, Agapitov O, Blake JB, Claudepierre SG. Electron Microburst Size Distribution Derived With AeroCube-6. J Geophys Res Space Phys 2020; 125:e2019JA027651. [PMID: 32714732 PMCID: PMC7375064 DOI: 10.1029/2019ja027651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
Microbursts are an impulsive increase of electrons from the radiation belts into the atmosphere and have been directly observed in low Earth orbit and the upper atmosphere. Prior work has estimated that microbursts are capable of rapidly depleting the radiation belt electrons on the order of a day; hence, their role to radiation belt electron losses must be considered. Losses due to microbursts are not well constrained, and more work is necessary to accurately quantify their contribution as a loss process. To address this question, we present a statistical study of > 35 keV microburst sizes using the pair of AeroCube-6 CubeSats. The microburst size distribution in low Earth orbit and the magnetic equator was derived using both spacecraft. In low Earth orbit, the majority of microbursts were observed, while the AeroCube-6 separation was less than a few tens of kilometers, mostly in latitude. To account for the statistical effects of random microburst locations and sizes, Monte Carlo and analytic models were developed to test hypothesized microburst size distributions. A family of microburst size distributions were tested, and a Markov chain Monte Carlo sampler was used to estimate the optimal distribution of model parameters. Finally, a majority of observed microbursts map to sizes less than 200 km at the magnetic equator. Since microbursts are widely believed to be generated by scattering of radiation belt electrons by whistler mode waves, the observed microburst size distribution was compared to whistler mode chorus size distributions derived in prior literature.
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Affiliation(s)
- M. Shumko
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - A. T. Johnson
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - J. G. Sample
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - B. A. Griffith
- Department of PhysicsMontana State UniversityBozemanMTUSA
| | - D. L. Turner
- Space Science Applications LaboratoryThe Aerospace CorportationEl SegundoCAUSA
| | - T. P. O'Brien
- Space Science Applications LaboratoryThe Aerospace CorportationEl SegundoCAUSA
| | - O. Agapitov
- Space Sciences LaboratoryUniversity of CaliforniaBerkeleyCAUSA
| | - J. B. Blake
- Space Science Applications LaboratoryThe Aerospace CorportationEl SegundoCAUSA
| | - S. G. Claudepierre
- Space Science Applications LaboratoryThe Aerospace CorportationEl SegundoCAUSA
- Department of Atmospheric and Oceanic SciencesUniversity of CaliforniaLos AngelesCAUSA
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