The Importance of Heat Flux in Quasi-Parallel Collisionless Shocks
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2023
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| author | Haggerty, Colby C. Caprioli, Damiano Cassak, Paul A. Barbhuiya, M. Hasan Wilson III, Lynn Turner, Drew |
| author_facet | Haggerty, Colby C. Caprioli, Damiano Cassak, Paul A. Barbhuiya, M. Hasan Wilson III, Lynn Turner, Drew |
| contents | Collisionless plasma shocks are a common feature of many space and astrophysical systems and are sources of high-energy particles and non-thermal emission, channeling as much as 20\% of the shock's energy into non-thermal particles. The generation and acceleration of these non-thermal particles have been extensively studied, however, how these particles feed back on the shock hydrodynamics has not been fully treated. This work presents the results of self-consistent hybrid particle-in-cell simulations that show the effect of self-generated non-thermal particle populations on the nature of collisionless, quasi-parallel shocks. They contribute to a significant heat flux density upstream of the shock. Non-thermal particles downstream of the shock leak into the upstream region, taking energy away from the shock. This increases the compression ratio, slows the shock down, and flattens the non-thermal population's spectral index for lower Mach number shocks. We incorporate this into a revised theory for the Rankine-Hugoniot jump conditions that include this effect and it shows excellent agreement with simulations. The results have the potential to explain discrepancies between predictions and observations in a wide range of systems, such as inaccuracies of predictions of arrival times of coronal mass ejections and the conflicting radio and x-ray observations of intracluster shocks.
These effects will likely need to be included in fluid modeling to accurately predict shock evolution. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_12423 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | The Importance of Heat Flux in Quasi-Parallel Collisionless Shocks Haggerty, Colby C. Caprioli, Damiano Cassak, Paul A. Barbhuiya, M. Hasan Wilson III, Lynn Turner, Drew Plasma Physics High Energy Astrophysical Phenomena Space Physics Collisionless plasma shocks are a common feature of many space and astrophysical systems and are sources of high-energy particles and non-thermal emission, channeling as much as 20\% of the shock's energy into non-thermal particles. The generation and acceleration of these non-thermal particles have been extensively studied, however, how these particles feed back on the shock hydrodynamics has not been fully treated. This work presents the results of self-consistent hybrid particle-in-cell simulations that show the effect of self-generated non-thermal particle populations on the nature of collisionless, quasi-parallel shocks. They contribute to a significant heat flux density upstream of the shock. Non-thermal particles downstream of the shock leak into the upstream region, taking energy away from the shock. This increases the compression ratio, slows the shock down, and flattens the non-thermal population's spectral index for lower Mach number shocks. We incorporate this into a revised theory for the Rankine-Hugoniot jump conditions that include this effect and it shows excellent agreement with simulations. The results have the potential to explain discrepancies between predictions and observations in a wide range of systems, such as inaccuracies of predictions of arrival times of coronal mass ejections and the conflicting radio and x-ray observations of intracluster shocks. These effects will likely need to be included in fluid modeling to accurately predict shock evolution. |
| title | The Importance of Heat Flux in Quasi-Parallel Collisionless Shocks |
| topic | Plasma Physics High Energy Astrophysical Phenomena Space Physics |
| url | https://arxiv.org/abs/2307.12423 |