Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density
A critical component of particle acceleration in astrophysical shocks is the nonresonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cell simulations to investigate...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adadf5 |
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| author | Emily Lichko Damiano Caprioli Benedikt Schroer Siddhartha Gupta |
| author_facet | Emily Lichko Damiano Caprioli Benedikt Schroer Siddhartha Gupta |
| author_sort | Emily Lichko |
| collection | DOAJ |
| description | A critical component of particle acceleration in astrophysical shocks is the nonresonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cell simulations to investigate the high-CR-current regime, where the typical assumptions underlying the Bell instability break down. Despite being more strongly driven, significantly less magnetic field amplification is observed than in low-current cases, an effect due to the anisotropic heating that occurs in this regime. We also find that electron-scale modes, despite being the fastest growing, mostly lead to moderate electron heating and do not affect the late evolution or saturation of the instability. |
| format | Article |
| id | doaj-art-10feb6eefe524ffb832a81172cc93d5a |
| institution | DOAJ |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-10feb6eefe524ffb832a81172cc93d5a2025-08-20T03:17:18ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01980224010.3847/1538-4357/adadf5Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current DensityEmily Lichko0https://orcid.org/0000-0003-1945-8460Damiano Caprioli1https://orcid.org/0000-0003-0939-8775Benedikt Schroer2https://orcid.org/0000-0002-4273-9896Siddhartha Gupta3https://orcid.org/0000-0002-1030-8012Department of Astronomy and Astrophysics, The University of Chicago , IL 60637, USA ; emily.r.lichko.civ@us.navy.mil; Plasma Physics Division , Naval Research Laboratory, Washington, DC 20375, USADepartment of Astronomy and Astrophysics, The University of Chicago , IL 60637, USA ; emily.r.lichko.civ@us.navy.mil; Enrico Fermi Institute, The University of Chicago , Chicago, IL 60637, USADepartment of Astronomy and Astrophysics, The University of Chicago , IL 60637, USA ; emily.r.lichko.civ@us.navy.milDepartment of Astronomy and Astrophysics, The University of Chicago , IL 60637, USA ; emily.r.lichko.civ@us.navy.mil; Department of Astrophysical Sciences, Princeton University , 4 Ivy Ln., Princeton, NJ 08544, USAA critical component of particle acceleration in astrophysical shocks is the nonresonant (Bell) instability, where the streaming of cosmic rays (CRs) leads to the amplification of magnetic fields necessary to scatter particles. In this work we use kinetic particle-in-cell simulations to investigate the high-CR-current regime, where the typical assumptions underlying the Bell instability break down. Despite being more strongly driven, significantly less magnetic field amplification is observed than in low-current cases, an effect due to the anisotropic heating that occurs in this regime. We also find that electron-scale modes, despite being the fastest growing, mostly lead to moderate electron heating and do not affect the late evolution or saturation of the instability.https://doi.org/10.3847/1538-4357/adadf5Plasma astrophysicsShocksPlasma physicsCosmic raysMagnetic fields |
| spellingShingle | Emily Lichko Damiano Caprioli Benedikt Schroer Siddhartha Gupta Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density The Astrophysical Journal Plasma astrophysics Shocks Plasma physics Cosmic rays Magnetic fields |
| title | Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density |
| title_full | Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density |
| title_fullStr | Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density |
| title_full_unstemmed | Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density |
| title_short | Understanding Streaming Instabilities in the Limit of High Cosmic-Ray Current Density |
| title_sort | understanding streaming instabilities in the limit of high cosmic ray current density |
| topic | Plasma astrophysics Shocks Plasma physics Cosmic rays Magnetic fields |
| url | https://doi.org/10.3847/1538-4357/adadf5 |
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