Kinetic Simulations of Cosmic-Ray-modified Shocks. II. Particle Spectra
Kinetic Simulations of Cosmic-Ray-modified Shocks. II. Particle Spectra
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DOI：
10.3847/1538-4357/abbe05
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发表时间：
2020-12-01
影响因子：
4.9
通讯作者：
Blasi, Pasquale
中科院分区：
文献类型：
--
作者：
Caprioli, Damiano;Haggerty, Colby C.;Blasi, Pasquale
扩散激波加速是在空间和天体物理系统中产生高能粒子的一种重要机制。长期以来，这种高能粒子一直被预测会影响激波的流体动力学结构，进而导致CR谱比测试粒子预测的更平坦。然而，在这项工作和一篇配套论文中，我们使用自洽混合(动离子-流体电子)模拟首次展示了CR修正的冲击实际上是如何产生更陡峭的光谱的。这种陡化是由嵌入在激波下游的磁湍流中的CRS平流增强所驱动的，在我们所说的“后游标”中。这些结果与对超新星和超新星残骸的多波长观测是一致的，并对一般的空间/天体物理冲击具有重要的现象学意义。
Diffusive shock acceleration is a prominent mechanism for producing energetic particles in space and in astrophysical systems. Such energetic particles have long been predicted to affect the hydrodynamic structure of the shock, in turn leading to CR spectra flatter than the test-particle prediction. However, in this work along with a companion paper, we use self-consistent hybrid (kinetic ion-fluid electron) simulations to show for the first time how CR-modified shocks actually produce steeper spectra. The steepening is driven by the enhanced advection of CRs embedded in magnetic turbulence downstream of the shock, in what we call the "postcursor." These results are consistent with multiwavelength observations of supernovae and supernova remnants and have significant phenomenological implications for space/astrophysical shocks in general.