Cross-field transport and pitch-angle anisotropy of solar energetic particles in MHD turbulence
Cross-field transport and pitch-angle anisotropy of solar energetic particles in MHD turbulence
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MHD 湍流中太阳高能粒子的跨场传输和俯仰角各向异性
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发表时间：
2015
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通讯作者：
F. Fraschetti
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作者：
F. Fraschetti
最近对太阳高能粒子通过日光层湍流传播的建模也在本讲习班上讨论，研究了俯仰角散射和垂直输运在太阳经度上粒子传播中的作用，如多航天器测量（STEREO A/B、ACE、SOHO等）所示。在不同的能量范围内，在1 Au。在某些情况下，颗粒分布的一阶俯仰角各向异性是不可忽略的。本文计算了两种MHD湍流模型（a）3-D各向同性模型和（B）Goldreich-Sridhar提出的各向异性模型在考虑俯仰角依赖性的非均匀湍流中由于梯度/曲率漂移引起的平均垂直位移。我们发现，在这两种情况下，漂移的规模为$（1-μ ^2）^2$与俯仰角的余弦$μ $，与以前的模型相比，SEP的运输。这一结果可能会影响SEP通过日光层传播的模型。
Recent modelling of solar energetic particles (SEPs) propagation through the heliospheric turbulence, also discussed in this workshop, has investigated the role of the pitch-angle scattering and the perpendicular transport in spreading particles in heliolongitude, as shown by multi-spacecraft measurements (STEREO A/B, ACE, SOHO, etc.) at 1 AU in various energy ranges. In some events the first-order pitch-angle anisotropy of the particles distribution is not-negligible. We calculate the average perpendicular displacement due to the gradient/curvature drift in an inhomogeneous turbulence accounting for pitch-angle dependence for two MHD turbulence models: (a) 3-D isotropic, (b) anisotropic as conjectured by Goldreich-Sridhar. We find in both cases that the drift scales as $(1-mu^2)^2$ with the cosine of pitch-angle $mu$, in contrast with previous models for transport of SEPs. This result can impact the models of propagation of SEPs through the heliosphere.