Magnetohydrodynamic waves linear evolution in parallel shear flows: Amplification and mutual transformations
Magnetohydrodynamic waves linear evolution in parallel shear flows: Amplification and mutual transformations
复制标题
平行剪切流中的磁流体动力波线性演化：放大和相互转换
DOI：
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
A. Tevzadze
中科院分区：
文献类型：
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作者：
G. Chagelishvili;R. Chanishvili;J. Lominadze;A. Tevzadze
研究了三维磁流体动力学（MHD）波[快磁子波（FMW），慢磁子波（SMW）和Alfven波]在无界平行流动中速度均匀剪切和沿流方向均匀磁场的演化。探讨了MHD波与背景流之间的能量交换。这一过程对于每种类型的波都有明显的不同，其特点是线性放大过程的不寻常（代数）行为。波浪线性演化过程的另一个新颖之处是，在广泛的系统（流和波）参数范围内，MHD波的耦合及其相互转换起源于有限的时间间隔。如果Alfven波最初是在剪切流动中产生的，则可能发生Alfven波向FMW的显著转变（取决于系统的参数）。采用非模态线性方法揭示这些结果是可能的，这种方法已广泛地应用于研究材料的演化。
Evolution of three-dimensional magnetohydrodynamic (MHD) waves [fast magnetosonic (FMW), slow magnetosonic (SMW) and Alfven waves] is studied in unbounded parallel flows with uniform shear of velocity and uniform magnetic field directed along the flow. The energy exchange between the MHD waves and background flow is explored. This process is noticeably different for each type of wave and is characterized by the unusual (algebraic) behavior of the linear amplification processes. Another novelty is shown in the wave linear evolution process — the coupling of MHD waves and their mutual transformations are originated in a limited time interval for a wide range of systems (flow and waves) parameters. Significant transformation of Alfven waves into FMW may take place (depending on the parameters of the system) if the former has been initially generated in shear flow. It is possible to reveal these results by employing the nonmodal linear approach which has been extensively used in the study of evolution of pert...