Magnetic reconnection in Z-pinch plasmas
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摘要: 分析了磁重联对晕等离子体加速和能量平衡过程的影响。分析表明晕等离子体向轴心的加速过程分为两个阶段:第一阶段晕等离子体在磁压或热压(依赖于丝数)作用下向轴心运动;第二阶段晕等离子体由于磁重联过程被加速到阿尔芬速度,并到达轴心形成先驱等离子体。估算表明重联层的厚度与离子的惯性长度具有相同的数量级,电流片内电子运动和离子的运动是解耦合的。在内爆滞止阶段电荷分离产生强的径向电场,这个电场将磁能转化为等离子体轴向(z方向)动能,内爆动能和轴向动能共同转化为X射线辐射能,以此解释了X射线能量大于内爆动能这一观测结果。分析了磁重联电磁脉冲的性质,对于1 MA驱动条件,电磁脉冲的总能量可达kJ量级。Abstract: Effects of magnetic reconnection on coronal plasma acceleration and energy balance have been discussed. Acceleration of coronal plasma to the array axis can be divided into two stages. Firstly, coronal plasma is pushed radially inward the array axis mainly by global magnetic force or thermal force, depending on the wire number. Secondly, plasma jets are accelerated to Alfven speed by magnetic reconnection, eventually reaching the array axis as precursor pinch. The thickness of the reconnection layer that is comparable to the ion inertial length indicates the motions of electrons and ions are decoupled in the current sheet. Strong radial electric field produced by charge separation converts magnetic energy to axial kinetic energy of plasmas, and thermalization of radial and axial kinetic energy accounts for radiation yield. For facilities with 1 MA drive level, the energy of electromagnetic pulse produced by magnetic reconnection can reach 1 kJ.
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Key words:
- magnetic reconnection /
- z-pinch /
- energy balance /
- electromagnetic pulse
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