On the Effects of Pickup Ion-driven Waves on the Diffusion Tensor of Low-energy Electrons in the Heliosphere
On the Effects of Pickup Ion-driven Waves on the Diffusion Tensor of Low-energy Electrons in the Heliosphere
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DOI：
10.3847/2041-8213/aa9372
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
N. E. Engelbrecht
中科院分区：
文献类型：
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作者：
N. E. Engelbrecht
本文研究了由于外日球层中拾取离子的形成而产生的阿尔文回旋波对低能电子输运系数的影响。为此，并行平均自由程（MFP）的表达式来自准线性理论，采用阻尼模型的动力学湍流。然后，这些被用作现有的表达式的垂直MFP和双折射降低漂移系数的输入。使用由两个组件的湍流传输模型产生的输出，所得到的扩散系数进行比较，使用一个更典型的假设湍流谱形式，忽略了皮卡离子产生的波的影响。据发现，包括拾取离子效应大大导致相当大的减少，在1-10 MeV电子的平行和垂直的MFP超过1000 Au，这被认为是有显着的后果，这些粒子的运输研究。
The effects of Alfvén cyclotron waves generated due to the formation in the outer heliosphere of pickup ions on the transport coefficients of low-energy electrons is investigated here. To this end, parallel mean free path (MFP) expressions are derived from quasilinear theory, employing the damping model of dynamical turbulence. These are then used as inputs for existing expressions for the perpendicular MFP and turbulence-reduced drift coefficient. Using outputs generated by a two-component turbulence transport model, the resulting diffusion coefficients are compared with those derived using a more typically assumed turbulence spectral form, which neglects the effects of pickup ion-generated waves. It is found that the inclusion of pickup ion effects greatly leads to considerable reductions in the parallel and perpendicular MFPs of 1–10 MeV electrons beyond ∼10 au, which are argued to have significant consequences for studies of the transport of these particles.