The Interaction of Low-Frequency Turbulence with Collisionless Shock Waves

冲击波和低频湍流在等离子体中无处不在，发生在各种各样的环境中，如喷气发动机、惯性约束聚变装置、行星际空间、地球的弓形激波和超新星。冲击和湍流之间的基本相互作用将通过两个互补的研究来解决。对于先前存在的上游湍流简单地转换为激波的情况，激波的平均位置和速度作为上游能量密度和湍流的函数，激波位置和速度的变化，激波对湍流的放大及其随后在下游的耗散都将通过复杂的数值模拟来评估。宽能量粒子介导的激波放大和传递了先前存在的湍流，但也通过激波加速的高能粒子梯度产生了额外的湍流。在这种情况下，高能粒子可以促进激波内的整体动量平衡。第二项研究旨在通过激波跳变建立热等离子体、超热加速粒子和相关磁流体动力学湍流的完全自洽模型。

Shock waves and low-frequency turbulence are ubiquitous in plasmas, occurring in environments as diverse as jet engines, inertial confinement fusion devices, interplanetary space, the Earth's bow-shock and supernovae. The fundamental interactions between shocks and turbulence will be addressed through two complementary studies. For situations in which pre-existing upstream turbulence is simply convected into a shock, the mean location and speed of the shock as a function of the upstream energy density and turbulence, the variance of the shock position and speed, the amplification of the turbulence by the shock and its subsequent dissipation downstream will all be assessed through sophisticated numerical simulations. Broad energetic-particle-mediated shocks amplify and transmit the pre-existing turbulence, but also generate additional turbulence through shock-accelerated energetic particle gradients. In this case, energetic particles can contribute to the overall momentum balance within the shock. The second study aims at developing a fully self-consistent model of the thermal plasma, the superthermal accelerated particles and the associated magnetohydrodynamic turbulence through a shock jump.