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Ruszkowski M, Pfrommer C. Cosmic ray feedback in galaxies and galaxy clusters: A pedagogical introduction and a topical review of the acceleration, transport, observables, and dynamical impact of cosmic rays. THE ASTRONOMY AND ASTROPHYSICS REVIEW 2023; 31:4. [PMID: 38115816 PMCID: PMC10730010 DOI: 10.1007/s00159-023-00149-2] [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: 06/05/2023] [Accepted: 10/05/2023] [Indexed: 12/21/2023]
Abstract
Understanding the physical mechanisms that control galaxy formation is a fundamental challenge in contemporary astrophysics. Recent advances in the field of astrophysical feedback strongly suggest that cosmic rays (CRs) may be crucially important for our understanding of cosmological galaxy formation and evolution. The appealing features of CRs are their relatively long cooling times and relatively strong dynamical coupling to the gas. In galaxies, CRs can be close to equipartition with the thermal, magnetic, and turbulent energy density in the interstellar medium, and can be dynamically very important in driving large-scale galactic winds. Similarly, CRs may provide a significant contribution to the pressure in the circumgalactic medium. In galaxy clusters, CRs may play a key role in addressing the classic cooling flow problem by facilitating efficient heating of the intracluster medium and preventing excessive star formation. Overall, the underlying physics of CR interactions with plasmas exhibit broad parallels across the entire range of scales characteristic of the interstellar, circumgalactic, and intracluster media. Here we present a review of the state-of-the-art of this field and provide a pedagogical introduction to cosmic ray plasma physics, including the physics of wave-particle interactions, acceleration processes, CR spatial and spectral transport, and important cooling processes. The field is ripe for discovery and will remain the subject of intense theoretical, computational, and observational research over the next decade with profound implications for the interpretation of the observations of stellar and supermassive black hole feedback spanning the entire width of the electromagnetic spectrum and multi-messenger data.
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Affiliation(s)
- Mateusz Ruszkowski
- Department of Astronomy, University of Michigan, 1085 S. University Ave., 323 West Hall, Ann Arbor, MI 48109-1107 USA
- Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, 85748 Garching, Germany
| | - Christoph Pfrommer
- Leibniz Institute for Astrophysics Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
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Bohdan A, Pohl M, Niemiec J, Morris PJ, Matsumoto Y, Amano T, Hoshino M, Sulaiman A. Magnetic Field Amplification by the Weibel Instability at Planetary and Astrophysical Shocks with High Mach Number. PHYSICAL REVIEW LETTERS 2021; 126:095101. [PMID: 33750160 DOI: 10.1103/physrevlett.126.095101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/07/2021] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Collisionless shocks are ubiquitous in the Universe and often associated with a strong magnetic field. Here, we use large-scale particle-in-cell simulations of nonrelativistic perpendicular shocks in the high-Mach-number regime to study the amplification of the magnetic field within shocks. The magnetic field is amplified at the shock transition due to the ion-ion two-stream Weibel instability. The normalized magnetic field strength strongly correlates with the Alfvénic Mach number. Mock spacecraft measurements derived from particle-in-cell simulations are fully consistent with those taken in situ at Saturn's bow shock by the Cassini spacecraft.
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Affiliation(s)
| | - Martin Pohl
- DESY, DE-15738 Zeuthen, Germany
- Institute of Physics and Astronomy, University of Potsdam, DE-14476 Potsdam, Germany
| | - Jacek Niemiec
- Institute of Nuclear Physics Polish Academy of Sciences, PL-31342 Krakow, Poland
| | | | - Yosuke Matsumoto
- Department of Physics, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan
| | - Takanobu Amano
- Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masahiro Hoshino
- Department of Earth and Planetary Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ali Sulaiman
- Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242, USA
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Lichko E, Egedal J. Magnetic pumping model for energizing superthermal particles applied to observations of the Earth's bow shock. Nat Commun 2020; 11:2942. [PMID: 32522987 PMCID: PMC7287107 DOI: 10.1038/s41467-020-16660-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/14/2020] [Indexed: 12/03/2022] Open
Abstract
Energetic particle generation is an important component of a variety of astrophysical systems, from seed particle generation in shocks to the heating of the solar wind. It has been shown that magnetic pumping is an efficient mechanism for heating thermal particles, using the largest-scale magnetic fluctuations. Here we show that when magnetic pumping is extended to a spatially-varying magnetic flux tube, magnetic trapping of superthermal particles renders pumping an effective energization method for particles moving faster than the speed of the waves and naturally generates power-law distributions. We validated the theory by spacecraft observations of the strong, compressional magnetic fluctuations near the Earth’s bow shock from the Magnetospheric Multiscale mission. Given the ubiquity of magnetic fluctuations in different astrophysical systems, this mechanism has the potential to be transformative to our understanding of how the most energetic particles in the universe are generated. Energetic particle generation is an important component of a variety of astrophysical systems. Here, the authors show when magnetic pumping is extended to a spatially-varying magnetic flux tube, magnetic trapping of superthermal particles renders pumping an effective energization method for particles moving faster than the speed of the waves.
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Affiliation(s)
- E Lichko
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA. .,Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA.
| | - J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, WI, USA
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Amano T, Katou T, Kitamura N, Oka M, Matsumoto Y, Hoshino M, Saito Y, Yokota S, Giles BL, Paterson WR, Russell CT, Le Contel O, Ergun RE, Lindqvist PA, Turner DL, Fennell JF, Blake JB. Observational Evidence for Stochastic Shock Drift Acceleration of Electrons at the Earth's Bow Shock. PHYSICAL REVIEW LETTERS 2020; 124:065101. [PMID: 32109113 DOI: 10.1103/physrevlett.124.065101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 11/18/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
The first-order Fermi acceleration of electrons requires an injection of electrons into a mildly relativistic energy range. However, the mechanism of injection has remained a puzzle both in theory and observation. We present direct evidence for a novel stochastic shock drift acceleration theory for the injection obtained with Magnetospheric Multiscale observations at the Earth's bow shock. The theoretical model can explain electron acceleration to mildly relativistic energies at high-speed astrophysical shocks, which may provide a solution to the long-standing issue of electron injection.
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Affiliation(s)
- T Amano
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
| | - T Katou
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
| | - N Kitamura
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
| | - M Oka
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA
| | - Y Matsumoto
- Department of Physics, Chiba University, Chiba 263-8522, Japan
| | - M Hoshino
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
| | - Y Saito
- Institute of Space and Astronautical Science, Sagamihara 252-5210, Japan
| | - S Yokota
- Department of Earth and Space Science, Osaka University, Toyonaka 560-0043, Japan
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C T Russell
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, California 90095, USA
| | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris-Sud/Obs. de Paris, Paris F-75252, France
| | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - D L Turner
- Space Sciences Department, The Aerospace Corporation, El Segundo, California 90245, USA
| | - J F Fennell
- Space Sciences Department, The Aerospace Corporation, El Segundo, California 90245, USA
| | - J B Blake
- Space Sciences Department, The Aerospace Corporation, El Segundo, California 90245, USA
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