Comment on the first-order Fermi acceleration at ultra-relativistic shocks
Comment on the first-order Fermi acceleration at ultra-relativistic shocks
复制标题
超相对论激波下的一阶费米加速评论
DOI：
10.1051/0004-6361:20021173
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发表时间：
2001
影响因子：
6.5
通讯作者：
J. Bednarz
中科院分区：
文献类型：
--
作者：
M. Ostrowski;M. Ostrowski;J. Bednarz
超相对论激波下的一阶费米加速过程有望产生具有唯一渐近谱指数1:2的粒子谱。下面，我们将讨论这一结果及其各种推导的差异，这些推导——明确地或隐含地——总是要求激波下游的高度湍流条件。在存在中等振幅湍流时，生成的粒子谱可能比上述渐近谱陡得多。我们也注意到在超相对论激波附近粒子输运的俯仰角扩散模型的应用问题。
The first-order Fermi acceleration process at an ultra-relativistic shock wave is expected to create a particle spectrum with the unique asymptotic spectral index 1 2:2. Below, we discuss this result and dierences in its various derivations, which - explicitly or implicitly - always require highly turbulent conditions downstream of the shock. In the presence of medium amplitude turbulence the generated particle spectrum can be much steeper than the above asymptotic one. We also note problems with application of the pitch angle diusion model for particle transport near the ultra-relativistic shocks.