Injection of thermal and suprathermal seed particles into coronal shocks of varying obliquity
Injection of thermal and suprathermal seed particles into coronal shocks of varying obliquity
复制标题
将热和超热种子粒子注入不同倾角的日冕震中
DOI：
10.1051/0004-6361/201321348
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发表时间：
2013
影响因子：
6.5
通讯作者：
Battarbee M
中科院分区：
文献类型：
--
作者：
Battarbee M
背景日冕中的扩散激波加速可以将太阳高能粒子加速到非常高的能量。加速效率是通过自身产生的波被捕获来提高的，这高度依赖于加速粒子的数量。这又取决于粒子注入加速过程的效率。目的我们分析了不同倾角的日冕激波的注入效率。我们通过反射和下游散射来评估注射，包括交叉激波电位的影响。对亚热和超温种子种群进行了分析。给出了激波下游交叉场扩散对喷射效率影响的结果。方法利用解析方法，给出了适用的喷射速度阈值，并与半解析通量积分和蒙特卡罗模拟进行了比较，后者不依赖于二元阈值。通过改变激波-法线角度θ和激波-法线速度Vs来评估注射效率与这些参数的关系。我们表明，下游各向同性方法影响这一结果的θBn依赖性。结果表明，对于日冕激波加速度的蒙特卡罗模拟而言，通过散射得到的下游各向同性分布函数对于真实模拟粒子注入是必要的。根据我们的结果，种子粒子在准平行日冕激波下的注入可以导致显著的加速效率，特别是当与变化的场线几何相结合时。
ContextDiffusive shock acceleration in the solar corona can accelerate solar energetic particles to very high energies. Acceleration efficiency is increased by entrapment through self-generated waves, which is highly dependent on the amount of accelerated particles. This, in turn, is determined by the efficiency of particle injection into the acceleration process.AimsWe present an analysis of the injection efficiency at coronal shocks of varying obliquity. We assessed injection through reflection and downstream scattering, including the effect of a cross-shock potential. Both quasi-thermal and suprathermal seed populations were analysed. We present results on the effect of cross-field diffusion downstream of the shock on the injection efficiency.MethodsUsing analytical methods, we present applicable injection speed thresholds that were compared with both semi-analytical flux integration and Monte Carlo simulations, which do not resort to binary thresholds. Shock-normal angleθBnand shock-normal velocityVswere varied to assess the injection efficiency with respect to these parameters.ResultsWe present evidence of a significant bias of thermal seed particle injection at small shock-normal angles. We show that downstream isotropisation methods affect theθBn-dependence of this result. We show a non-negligible effect caused by the cross-shock potential, and that the effect of downstream cross-field diffusion is highly dependent on boundary definitions.ConclusionsOur results show that for Monte Carlo simulations of coronal shock acceleration a full distribution function assessment with downstream isotropisation through scatterings is necessary to realistically model particle injection. Based on our results, seed particle injection at quasi-parallel coronal shocks can result in significant acceleration efficiency, especially when combined with varying field-line geometry.
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影响因子：
6.5
作者：
R. Vainio
通讯作者：
R. Vainio
重新审视激波前沿的离子反射
影响因子：
--
作者：
M. Gedalin
通讯作者：
M. Gedalin
DOI：
10.1016/j.jastp.2007.08.064
发表时间：
2008
影响因子：
1.9
作者：
R. Vainio;T. Laitinen
通讯作者：
T. Laitinen
无碰撞冲击波的计算机模拟
DOI：
--
发表时间：
1984
期刊：
影响因子：
--
作者：
M. Leroy
通讯作者：
M. Leroy
倾斜冲击下粒子加速的蒙特卡罗模拟：包括交叉场扩散
影响因子：
2.6
作者：
M. Baring;D. Ellison;F. C. Jones
通讯作者：
F. C. Jones