The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows
The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows
复制标题
脉冲功率驱动等离子体流中 3D 碰撞磁化弓激波的结构
DOI：
10.1017/s0022377822001118
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发表时间：
2022
影响因子：
2.5
通讯作者：
Hare, J.D.
中科院分区：
文献类型：
--
作者：
Datta, R.;Russell, D.R.;Tang, I.;Clayson, T.;Suttle, L.G.;Chittenden, J.P.;Lebedev, S.V.;Hare, J.D.
我们调查三维（3-D）弓冲击高度碰撞磁化铝等离子体，在烧蚀阶段的爆炸线阵列上的MAGPIE设施（1.4 MA，240纳秒）产生的。从金属丝阵列烧蚀等离子体产生径向发散的超音速（）。这些气流与放置在气流中的感应探头碰撞，感应探头既作为产生磁化弓形激波的障碍物，又作为平流磁场的诊断。沿着两条正交视线的激光干涉法被用来测量线积分电子密度。由于等离子体的电阻扩散长度与探针的尺寸相当，磁场从激波前沿的离子流体中扩散出来，产生流体动力激波，其结构由音速马赫数决定，而不是流的磁音速马赫数。使用电阻磁流体动力学（MHD）代码Gorgon进行的3-D模拟证实了这一点，但低估了实验弓形激波形状中观察到的各向异性，这表明非MHD机制可能对修改激波结构很重要。
We investigate three-dimensional (3-D) bow shocks in a highly collisional magnetized aluminium plasma, generated during the ablation phase of an exploding wire array on the MAGPIE facility (1.4 MA, 240 ns). Ablation of plasma from the wire array generates radially diverging, supersonic (). These flows collide with an inductive probe placed in the flow, which serves both as the obstacle that generates the magnetized bow shock, and as a diagnostic of the advected magnetic field. Laser interferometry along two orthogonal lines of sight is used to measure the line-integrated electron density. A detached bow shock forms ahead of the probe, with a larger opening angle in the plane parallel to the magnetic field than in the plane normal to it. Since the resistive diffusion length of the plasma is comparable to the probe size, the magnetic field decouples from the ion fluid at the shock front and generates a hydrodynamic shock, whose structure is determined by the sonic Mach number, rather than the magnetosonic Mach number of the flow. The 3-D simulations performed using the resistive magnetohydrodynamic (MHD) code Gorgon confirm this picture, but under-predict the anisotropy observed in the shape of the experimental bow shock, suggesting that non-MHD mechanisms may be important for modifying the shock structure.