A Study of Electron Forbush Decreases with a 3D SDE Numerical Model
A Study of Electron Forbush Decreases with a 3D SDE Numerical Model
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用3D SDE数值模型研究电子叉减
DOI：
10.3847/1538-4357/aac5f2
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Feng Xueshang
中科院分区：
文献类型：
--
作者：
Luo Xi;Potgieter Marius S.;Zhang Ming;Feng Xueshang
由于PAMELA和AMS 02对宇宙线电子通量的精确测量，最近首次观测到电子福布什减少（Fds）。这是一个动机，以执行一个先进的时间依赖性，三维（3D）随机微分方程模型，研究质子FDS早期的电子福布什减少的数值研究。该模型包括一个现实的星际电子光谱重建旅行者观测，扩散和漂移系数再现调制的光谱PAMELA在2009年观察到的。在此数值模型的基础上，模拟了一系列刚性的电子Fd分布。此外，在不同的太阳极性时期的电子和质子Fds进行了系统的比较。这种方法提供了深入了解的刚性依赖的日光层扩散系数和漂移效应在两个磁场极性周期。我们发现，在A> 0的时期，1 GV质子Fd的恢复时间明显短于1 GV电子，而电子Fd显示出更快的恢复在A <0的时期。该模型清楚地预测了Fds的恢复时间中的电荷符号依赖性效应，但其幅度较小。
Because of the precise measurements of the cosmic ray electron flux by the PAMELA and AMS02, Electron Forbush decreases (Fds) have recently been observed for the first time. This serves as motivation to perform a numerical study of electron Forbush decreases with an advanced time-dependent, three-dimensional (3D) stochastic differential equation model, developed earlier to study proton Fds. The model includes a realistic interstellar electron spectrum reconstructed from Voyager observations, and diffusion and drift coefficients to reproduce the modulated spectrum observed by PAMELA in 2009. On the basis of this numerical model, electron Fd profiles for a range of rigidities are simulated. In addition, a systematic comparison between electron and proton Fds during different solar polarity epochs is performed. This approach gives insight into the rigidity dependence of the heliospheric diffusion coefficients and of drift effects over two magnetic field polarity cycles. We find that during an A > 0 epoch, the recovery time of a 1 GV proton Fd is remarkably shorter than the 1 GV electrons, whereas the electron Fd display a faster recovery during an A < 0 epoch. This model clear predicts a charge-sign dependent effect in the recovery time of Fds but less so for their magnitude.