Numerical studies on ultrarelativistic ion motions in an oblique magnetosonic shock wave
Numerical studies on ultrarelativistic ion motions in an oblique magnetosonic shock wave
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DOI：
10.1063/1.3270110
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发表时间：
2009-12
影响因子：
2.2
通讯作者：
S. Usami;R. Horiuchi;Y. Ohsawa
中科院分区：
文献类型：
--
作者：
S. Usami;R. Horiuchi;Y. Ohsawa
用解析和数值方法研究了磁声斜激波中超相对论离子的运动。零级理论预言，当激波速度为Vsh∼c cosθ时，斜激波可以使离子沿几乎平行于磁场的方向加速，其中θ是波法向和磁场之间的夹角，而扰动是一个几乎垂直于零级运动的一维振荡。摄动频率ω为Ωi0γ−1/2量级，其中γ是零阶速度的洛伦兹因子。这些理论预测用测试粒子模拟进行了验证，其中测试粒子轨道是利用从电磁粒子模拟获得的冲击波的电磁场来计算的。用该理论解释了仿真中的零阶和摄动运动。
The motion of ultrarelativistic ions in an oblique magnetosonic shock wave is studied analytically and numerically. The zeroth-order theory predicts that an oblique shock wave can accelerate ions in the direction nearly parallel to the magnetic field if the shock speed is vsh∼c cos θ, where θ is the angle between the wave normal and the magnetic field, while the perturbation is a one-dimensional oscillation nearly perpendicular to the zeroth-order motion. The perturbation frequency ω is of the order of Ωi0γ−1/2, where γ is the Lorentz factor of the zeroth-order velocity. These theoretical predictions are examined with test particle simulations, in which the test particle orbits are calculated with use of the electromagnetic fields of a shock wave obtained from an electromagnetic particle simulation. The zeroth-order and perturbed motions in the simulations are explained by the theory.