Linear and Nonlinear Wave Processes in the Plasma Medium (Physics)

这项研究的目的是发展一种数学形式，用于分析复杂几何条件下的等离子体波行为。重点放在MHD波上，但也将考虑更高频率的波。MHD波的非线性相互作用可以产生各种重要的效应，影响等离子体中的加热、不稳定性、湍流和输运。一个例子是非线性Alfven波，它通过将波的螺旋度转换为平衡磁场的螺旋度来感应电流通道。这种转换有助于产生等离子体电流，并导致加热和等离子体不稳定。此外，圆偏振的Alfven波可以耦合成漂移波，并演化成局域涡旋结构，从而在涡旋结构内产生输运。所有这些都将以实验室和空间等离子体为重点进行较详细的探讨。所涉及的领域包括：1.质量流对MHD波活动的影响2.日冕中的MHD过程3.阿尔芬波螺旋度的输送和注入4.Alfven涡结构的激发5.等离子体波的非线性混合引起的位相共轭。

The objective of the research is to develop a mathematical formalism for analyzing plasma wave behavior under complicated geometrical conditions. Emphasis is placed on MHD waves although waves of higher frequency will also be considered. Non-linear interaction of MHD waves can produce a variety of important effects that influence heating, instability, turbulence and transport in plasmas. An example is non-linear Alfven waves which induce current channels via conversion of wave helicity into helicity of the equilibrium magnetic field. This conversion contributes to the plasma current and leads to heating and plasma instability. In addition, circularly polarized Alfven waves can couple to drift waves and evolve into localized vortex structures which give rise to transport within the vortex structures. These will all be explored in some detail with emphasis on laboratory and space plasmas. The areas covered include: 1. Mass flow effects on MHD wave activity 2. MHD processes in the solar corona 3. Transport and injection of Alfven wave helicity 4. Excitation of Alfven vortex structures 5. Phase conjugation via non-linear mixing of plasma waves.