论文标题
磁场阻尼阻碍弱碰撞的非磁性等离子体中的发电机
Dynamo in weakly collisional nonmagnetized plasmas impeded by Landau damping of magnetic fields
论文作者
论文摘要
我们对已知在磁性水力动力学（MHD）中产生发电机的流量进行完全动力学模拟，考虑了雷诺数较低的场景和高磁性prandtl数量，与星系簇量表波动发电机有关。我们发现电子上的Landau阻尼会导致磁扰动的快速衰减，并阻碍了发电机。这种无碰撞阻尼过程在空间尺度上运行，在该空间尺度上，电子被非磁性化，从而降低了磁场在高磁场中生长的尺度范围，以高磁性prandtl数量波动发电机。当电子未被磁性磁性降低到电阻尺度时，磁能谱有望受到对应于磁性磁阻尼的比例，或者如果较小的（如果较小）电子吉拉迪乌斯尺度，而不是电阻尺度。因此，在模拟中，我们观察到电阻性MHD预测发电机的衰减磁场。
We perform fully kinetic simulations of flows known to produce dynamo in magnetohydrodynamics (MHD), considering scenarios with low Reynolds number and high magnetic Prandtl number, relevant for galaxy cluster scale fluctuation dynamos. We find that Landau damping on the electrons leads to a rapid decay of magnetic perturbations, impeding the dynamo. This collisionless damping process operates on spatial scales where electrons are nonmagnetized, reducing the range of scales where the magnetic field grows in high magnetic Prandtl number fluctuation dynamos. When electrons are not magnetized down to the resistive scale, the magnetic energy spectrum is expected to be limited by the scale corresponding to magnetic Landau damping or, if smaller, the electron gyroradius scale, instead of the resistive scale. In simulations we thus observe decaying magnetic fields where resistive MHD would predict a dynamo.
