The Interaction of Low-Frequency Turbulence with Collisionless Shock Waves

低频湍流与无碰撞冲击波的相互作用

• 批准号: 0317509
• 负责人: Gary Zank
• 金额: $ 37.56万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0317509&HistoricalAwards=false
• 关键词: Interaction; Low; Frequency; Turbulence; Collisionless

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.

冲击波和低频湍流在等离子体中无处不在，发生在喷气发动机、惯性约束聚变装置、行星际空间、地球弓激波和超新星等各种环境中。激波和湍流之间的基本相互作用将通过两项互补的研究来解决。对于简单地将上游存在的湍流转化为激波的情况，激波的平均位置和速度随上游能量密度和湍流的变化、激波位置和速度的变化、激波对湍流的放大和下游的耗散都将通过复杂的数值模拟来评估。广泛的高能粒子介导的激波放大和传输了先前存在的湍流，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，高能粒子可以对激波内部的整体动量平衡做出贡献。第二个研究旨在通过激波跳跃建立热等离子体、超热加速粒子和与之相关的磁流体力学湍流的完全自洽模型。