Transient and Turbulent Fields in Plasmas

目前正在进行有关磁化等离子体中电流和热脉冲输运的瞬态效应的实验研究，以及有关波动磁场中相干结构的湍流研究。这些过程解决了等离子体的基本特性，这些特性对于理解等离子体中的输运至关重要，它们在惯性和磁聚变、脉冲功率以及空间等离子体的主动实验中具有广泛的兴趣。所建议的工作将在具有出色诊断能力的大型受控实验室等离子体中进行。脉冲电流由电极、粒子束施加，并由磁天线感应。本文将研究这些电流在动态阿尔芬波、哨声和波束模式等电磁波中的输运。热脉冲是由磁性天线的脉冲、强射频场产生的。近无碰撞等离子体中的热输运不能用经典的扩散模型来描述，而可能涉及双层和非麦克斯韦分布。使用定向速度分析仪，发射电场探针和矢量磁场探针可在三维空间中移动，将产生场和粒子的详细图像。磁湍流将从热水平到环境场的水平进行研究。它是由在回旋加速器谐波频率下形成相干射频结构的粒子束中的电流波动或由高β等离子体中产生光束的哨声和较低混合湍流等不稳定性激发的。使用条件平均，一种特殊的统计技术，利用数字示波器，可以在湍流场中分辨出相干磁结构。这些“岛屿”中的场和粒子将被绘制出来，以便在微观尺度上研究传输过程。将开发精细化的血浆诊断工具和技术。这些详细的实验有望提高对等离子体基本特性的认识，对等离子体的各种用途具有重要意义，并培养学生在现代实验等离子体物理学方面的能力。

Experimental research is being pursued on transient effects dealing with the transport of current and heat pulses in magnetized plasmas and turbulence studies dealing with coherent structures in fluctuating magnetic fields. These processes address fundamental plasma properties which are essential for understanding transport in plasmas, and they are of broad interest in inertial and magnetic fusion, pulsed power, and for active experiments in space plasmas. The proposed work will be performed in a large, controlled laboratory plasma with excellent diagnostic capabilities. Pulsed currents are imposed with electrodes, particle beams and induced by magnetic antennas. The transport of these currents by electromagnetic waves such as kinetic Alfven waves, whistlers and beam modes will be studied. Heat pulses are generated with pulsed, intense rf fields of magnetic antennas. The heat transport in nearly collisionless plasmas cannot be described by classical diffusion models but may involve double layers and non- Maxwellian distributions. Using directional velocity analyzers, emissive electric field probes and vector magnetic field probes moveable in 3 dimensions will yield a detailed picture of fields and particles. Magnetic turbulence will be investigated from the thermal level to that of the ambient field. It is excited by current fluctuations in particle beams forming coherent rf structures at cyclotron harmonic frequencies or by instabilities such as beam-generating whistlers and lower hybrid turbulence in high-beta plasmas. Using conditional averaging, a special statistical technique employing digital oscilloscopes, coherent magnetic structure can be resolved in a turbulent field. Fields and particles in such "islands" will be mapped so as to study transport processes on a microscopic scale. Refined plasma diagnostic tools and techniques will be developed. Such detailed experiments are expected to advance the knowledge of basic plasma properties, have i mplications to the various uses of plasmas, and train students in modern experimental plasma physics.