...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physica Scripta: An International Journal for Experimental and Theoretical Physics >Experimental study of the dynamics of a thin current sheet
【24h】

Experimental study of the dynamics of a thin current sheet

机译：薄电流片动力学的实验研究

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Many plasmas in natural settings or in laboratory experiments carry currents. In magnetized plasmas the currents can be narrow field-aligned filaments as small as the electron inertial length (c/w(pe)) in the transverse dimension or fill the entire plasma column. Currents can take the form of sheets, again with the transverse dimension the narrow one. Are laminar sheets of electric current in a magnetized plasma stable? This became an important issue in the 1960s when current-carrying plasmas became key in the quest for thermonuclear fusion. The subject is still under study today. The conditions necessary for the onset for tearing are known, the key issue is that of the final state. Is there a final state? One possibility is a collection of stable tubes of current. On the other hand, is the interaction between the current filaments which are the byproduct endless, or does it go on to become chaotic? The subject of three-dimensional current systems is intriguing, rich in a variety of phenomena on multiple scale sizes and frequencies, and relevant to fusion studies, solar physics, space plasmas and astrophysical phenomena. In this study a long (delta z = 11m) and narrow (delta x = 1 cm, delta y = 20 cm) current sheet is generated in a background magnetoplasma capable of supporting Alfven waves. The current is observed to rapidly tear into a series of magnetic islands when viewed in a cross-sectional plane, but they are in essence three-dimensional flux ropes. At the onset of the current, magnetic field line reconnection is observed between the flux ropes. The sheet on the whole is kink-unstable, and after kinking exhibits large-scale, low-frequency (f f(ci)) rotation about the background field with an amplitude that grows with distance from the source of the current. Three-dimensional data of the magnetic and electric fields is acquired throughout the duration of the experiment and the parallel resistivity is derived from it. The parallel resistivity, for the most part, is not largest in the reconnection regions, but peaks in the neighborhood of large current gradients. At early times a quasi-separatrix layer (QSL) is observed where the current sheet tears, but later on a QSL of larger value, not obviously associated with reconnection, is measured at the edge of the current sheet. This QSL enhancement is connected with the rapidly spatially diverging magnetic fields in the moving sheet (ropes).
机译：在自然环境中或实验室实验中，许多等离子体会携带电流。在磁化等离子体中，电流可以是与横向尺寸一样小的电子惯性长度（c / w（pe））的窄场取向灯丝，也可以充满整个等离子体柱。电流可以采取薄板的形式，其横向尺寸还是窄的。磁化等离子体中的层流电流是否稳定？在1960年代，当载流等离子体成为寻求热核聚变的关键时，这成为一个重要的问题。今天该主题仍在研究中。撕裂开始的必要条件是已知的，关键问题是最终状态。有最终状态吗？一种可能性是收集稳定的电流管。另一方面，作为副产物的当前细丝之间的相互作用是无限的，还是会变得混乱？三维电流系统的主题很有趣，在多种尺度大小和频率上都具有丰富的现象，并且与聚变研究，太阳物理学，空间等离子体和天体物理学现象有关。在这项研究中，在能够支持Alfven波的背景磁浆中，产生了长电流（δz = 11m）和窄电流（δx = 1 cm，δy = 20 cm）。当在横截面中观察时，观察到电流迅速撕成一系列磁岛，但实际上它们是三维磁通绳。在电流开始时，在磁力线之间观察到磁场线重新连接。整个片材是扭结不稳定的，并且在扭结之后表现出围绕背景场的大规模，低频（f f（ci））旋转，其幅度随着距电流源距离的增加而增大。在整个实验过程中获取磁场和电场的三维数据，并从中得出平行电阻率。在大多数情况下，并联电阻率在重新连接区域中不是最大，但在大电流梯度附近会达到峰值。早期观察到准分割线层（QSL），其中当前工作表撕裂，但后来在较大值的QSL上测量了当前工作表的边缘（与重新连接没有明显关联）。这种QSL增强与活动纸（绳）中空间上迅速发散的磁场有关。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号