主要内容:
根据外部介质密度分为不同的情形，有的能产生反向激波，有的不能。。。
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文章信息:
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- · arXiv e-print (arXiv:1109.5314)
- · References in the Article
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| Title: |
| Interaction of a highly magnetized impulsive relativistic flow with an external medium |
| Authors: |
| Granot, Jonathan |
| Publication: |
| eprint arXiv:1109.5314 |
| Publication Date: |
| 09/2011 |
| Origin: |
| ARXIV |
| Keywords: |
| Astrophysics - High Energy Astrophysical Phenomena |
| Comment: |
| 53 pages, 10 figures, accepted to MNRAS (the abstract and introduction are now easier to follow) |
| Bibliographic Code: |
| 2011arXiv1109.5314G |
Abstract
Important astrophysical sources, such as gamma-ray bursts (GRBs) or tidal disruption events, are impulsive -- strongly varying with time. These outflows are likely highly magnetized near the central source, but their interaction with the external medium is not yet fully understood. Here I consider the combined impulsive magnetic acceleration of an initially highly magnetized shell of plasma and its deceleration by the external medium. I find four main dynamical regimes, that (for a given outflow) depend on the external density. (I) For small enough external densities the shell becomes kinetically dominated before it is significantly decelerated, thus reverting to the familiar unmagnetized "thin shell" case, which produces bright reverse shock emission that peaks well after the prompt GRB. (II) For larger external densities the shell remains highly magnetized and the reverse shock is strongly suppressed. It eventually transfers most of its energy through pdV work to the shocked external medium, whose afterglow emission peaks on a timescale similar to the prompt GRB duration. (III) For even larger external densities there is no initial impulsive acceleration phase. (IV) For the highest external densities the flow remains Newtonian.
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