Ion reflection at the shock front revisited
Ion reflection at the shock front revisited
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重新审视激波前沿的离子反射
DOI：
10.1029/95ja03669
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发表时间：
1996
影响因子：
--
通讯作者：
M. Gedalin
中科院分区：
文献类型：
--
作者：
M. Gedalin
我们研究了离子反射的过程中，在结构化的垂直冲击波阵面，在该过程中，离子穿过斜坡，进行过冲，转回斜坡，并再次穿越它，被观察到在上游区域的反射回旋离子。我们推导了反射条件，它取决于潜在的，磁压缩比和增加的矢势在脚和斜坡。理论的发展，说明了直接数值分析的离子轨迹模型结构化冲击波前。模型激波的参数选择接近于所观察到的βi ≥ 1的高马赫数超临界激波的参数。分析表明，脚长与镜面反射模型预测的值有很大不同，并且也取决于βi。对于βi ≤ 1的模型激波，所得到的足长与具有类似参数的激波的观测和模拟结果吻合得很好。它还表明，在脚的外缘和下游的反射离子速度与测量的观测误差的范围内同意。
We study the process of ion reflection at the structured perpendicular shock front, in which ions cross the ramp, proceed to the overshoot, turn back to the ramp, and cross it again, being observed in the upstream region as reflected-gyrating ions. We derive analytically the reflection condition which depends on the potential, magnetic compression ratio and increase of the vector potential across the foot and ramp. The theoretical developments are illustrated by direct numerical analysis of ion trajectories in a model structured shock front. The parameters of the model shock are chosen close to the parameters of the observed high-Mach number supercritical shock with βi ∼ 1. The analysis shows that the foot length differs substantially from the value predicted by the specular reflection model and depends on βi as well. The foot length found for the model shock with βi ∼ 1 is in a good agreement with observations and simulations of shocks with similar parameters. It is also shown that the reflected ion velocities at the outer edge of the foot and downstream agree with measurements within the limits of the observational errors.