Numerical Modeling of Electron Transport in Solar Wind: Effects of Whistler Turbulence and Coulomb Collisions
Numerical Modeling of Electron Transport in Solar Wind: Effects of Whistler Turbulence and Coulomb Collisions
复制标题
DOI：
10.1088/1742-6596/1100/1/012025
复制
发表时间：
2018-07
期刊：
影响因子：
--
通讯作者：
B. Tang;G. Zank;V. Kolobov
中科院分区：
文献类型：
--
作者：
B. Tang;G. Zank;V. Kolobov
太阳风中的电子分布函数（eVDF）明显偏离平衡麦克斯韦分布，由麦克斯韦核、超热晕、场向分量strahl和高能超晕组成。带电粒子的库仑碰撞在使这样的速度分布松弛到几个太阳半径之外是无效的。因此，需要考虑波粒相互作用。在描述电子与哨声波相互作用的动力学方程中引入了波粒相互作用项和粒子碰撞项。动力学方程的形式是一个对流扩散方程，其中的对流和扩散系数描述了电子在哨声湍流中的散射和阻力。发展了一种可靠的数值方法来求解完整形式的对流扩散类动力学方程。给出了数值方法在太阳风电子问题中的初步应用。对库仑碰撞和共振波粒子相互作用下的电子VDF进行了比较和分析。
The electron distribution function (eVDF) in the solar wind deviates significantly from an equilibrium Maxwellian distribution, and is comprised of a Maxwellian core, a suprathermal halo, a field-aligned component strahl, and a higher energy superhalo. Charged particle Coulomb collisions are ineffective in relaxing such a velocity distribution beyond a few solar radii. Therefore wave-particle interactions need to be considered. A wave-particle interaction term was introduced into the kinetic equation that describes the interaction of electrons with whistler waves, as well as particle collision terms. The kinetic equation has the form of an advection-diffusion-like equation in which the advection and diffusion coefficients describe the scattering and drag of electrons in whistler turbulence. A reliable numerical method has been developed to solve a full form of the advection-diffusion-like kinetic equation. Preliminary applications of the numerical method to the solar wind electron problem are presented. Comparison and analysis of the electron VDFs in the presence of Coulomb collisons and resonant wave-partcicle interactions are made.