Bohdan Artem, Pohl Martin, Niemiec Jacek, Morris Paul J, Matsumoto Yosuke, Amano Takanobu, Hoshino Masahiro, Sulaiman Ali
DESY, DE-15738 Zeuthen, Germany.
Institute of Physics and Astronomy, University of Potsdam, DE-14476 Potsdam, Germany.
Phys Rev Lett. 2021 Mar 5;126(9):095101. doi: 10.1103/PhysRevLett.126.095101.
Collisionless shocks are ubiquitous in the Universe and often associated with a strong magnetic field. Here, we use large-scale particle-in-cell simulations of nonrelativistic perpendicular shocks in the high-Mach-number regime to study the amplification of the magnetic field within shocks. The magnetic field is amplified at the shock transition due to the ion-ion two-stream Weibel instability. The normalized magnetic field strength strongly correlates with the Alfvénic Mach number. Mock spacecraft measurements derived from particle-in-cell simulations are fully consistent with those taken in situ at Saturn's bow shock by the Cassini spacecraft.
无碰撞激波在宇宙中无处不在，且常常与强磁场相关联。在此，我们使用高马赫数 regime 中非相对论性垂直激波的大规模粒子模拟来研究激波内磁场的放大。由于离子 - 离子双流韦贝尔不稳定性，磁场在激波过渡处被放大。归一化磁场强度与阿尔文马赫数密切相关。从粒子模拟得出的模拟航天器测量结果与卡西尼号航天器在土星弓形激波处原位测量的结果完全一致。
