A Cyclotron Maser Instability with Application to Space and Laboratory Plasmas
A Cyclotron Maser Instability with Application to Space and Laboratory Plasmas
复制标题
回旋脉泽不稳定性及其在空间和实验室等离子体中的应用
DOI：
10.1238/physica.topical.116a00023
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发表时间：
2005
期刊：
影响因子：
2.9
通讯作者：
R. Bingham
中科院分区：
文献类型：
--
作者：
R. A. Cairns;D. Speirs;K. Ronald;I. Vorgul;B. Kellett;A. Phelps;R. Bingham
当电子束进入会聚磁场时，由于磁矩守恒，速度分布函数呈现马蹄形。几年前，有人指出，这种分布是不稳定的回旋脉泽型不稳定性，并建议这种不稳定性可能是极光公里辐射的来源（宾厄姆，R。和凯恩斯，R.一、等离子体7，3089（2000））。以及某些类型的星星的发射（Bingham，R.，凯恩斯河A.和Kellett，B. J.，太空人。太空人。370，1000（2001））。在这里，我们提出了更多关于这个主题的最新工作。由于描述不稳定性的色散关系仅取决于磁场增加的因素以及波等离子体和回旋频率的比率，因此可以将效应缩放到实验室尺寸。斯特拉斯克莱德大学正在为此进行一项实验，预计将于2004年夏季投入使用。其目的是研究这种机制是否可能产生一个有用的辐射源，以及给出一个实验室模拟极光公里辐射。介绍了该实验的设计和现状。在理论方面，我们讨论了计算机模拟显示的不稳定性和准线性饱和的几何实验。我们还描述了一个更详细的理论的线性不稳定性比我们在以前的工作。生长速率已计算出在圆柱形几何形状与各种电子束配置和不同的圆柱模式结构。这些，以及模拟，支持我们早期工作的结论，即不稳定性具有高增长率。
When a beam of electrons moves into a converging magnetic field, the velocity distribution function takes on a horseshoe shape as a result of conservation of magnetic moment. A few years ago it was pointed out that such a distribution is unstable to a cyclotron maser type of instability and it was suggested that this instability might be the source of auroral kilometric radiation (Bingham, R. and Cairns, R. A., Phys. Plasmas 7, 3089 (2000).) and also of emission from certain types of star (Bingham, R., Cairns, R. A. and Kellett, B. J., Astron. Astrophys. 370, 1000 (2001).). Here we present more recent work on this topic. Since the dispersion relation which describes the instability only depends on the factor by which the magnetic field increases and on ratios of the wave plasma and cyclotron frequencies, it is possible to scale the effect to laboratory dimensions. An experiment to do this is being carried out at the University of Strathclyde and is expected to be operational during the summer of 2004. The objective is to investigate whether this mechanism might produce a useful radiation source, as well as to give a laboratory simulation of auroral kilometric radiation. The design of this experiment and its current status are described. On the theoretical side we discuss computer simulations showing the instability and its quasilinear saturation in the geometry of the experiment. We also describe a much more detailed theory of the linear instability than we have presented in previous work. Growth rates have been calculated in cylindrical geometry with various electron beam configurations and different cylindrical mode structures. These, and the simulations, support the conclusion of our earlier work that the instability has a high growth rate.