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，发生在像喷气发动机一样多样化，惯性限制融合装置，行星际空间，地球的弓箭和超新星。 冲击与湍流之间的基本相互作用将通过两项互补研究来解决。 对于预先存在上游湍流的情况，简单地将冲击的平均位置和速度与上游能量密度和湍流函数相关，冲击位置和速度的方差，震动的扩增被冲击及其随后的耗散下游的消散都将通过复杂的数值进行评估。 广泛的能量粒子介导的冲击会扩大并传递先前存在的湍流，但也通过冲击加速的能量颗粒梯度产生额外的湍流。 在这种情况下，能量颗粒可以有助于冲击中的整体动量平衡。 第二项研究旨在通过冲击跳跃开发热等离子体，超热加速颗粒和相关的磁性水动力湍流的完全自洽模型。