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Sawtooth Oscillation and Plasma Disruption in a Shear of Rotating Angular Velocity

旋转角速度剪切中的锯齿振荡和等离子体破坏

基本信息

批准号：
10680455
负责人：
SAEKI Koichi
金额：
$ 2.05万
依托单位：
Shizuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10680455/
关键词：
Plasma disruption Disruption Shear of rotating angular velocity Mode transition Plasma diffusion Sawtooth oscillation Radial electric field

项目摘要

As a result of this investigation, we got more detailed data concerning the nonlinearly developing process of the plasma disruption caused by the sear of rotating angular velocity, which was obtained preliminary last year.1. In order to test the method observing the behavior of the plasma density on the plane perpendicular to the magnetic field by the multi probes developed last year, we have applied this method to the drift waves, and succeeded to get the preliminary data of the drift-wave vortices drifting with the speed of the drift wave. Thus, we could show the high ability of this 2D measuring system. Unfortunately, we could not succeed the 2D observation of the sawtooth oscillation and the plasma disruption, although we observed the plasma diffusion in a shear of rotating angular velocity. This is because the lack of reproducibility as a results of insufficient controlling the sawtooth oscillation and the plasma disruption. Now, we are making an effort to improve this point.2. Thus, we observed, not the 2D contour lines date, but the direct date from the multi probes by using the oscilloscope, and discussed the relation between the sawtooth oscillation and the plasma disruption in detail. As a results of investigation, it became clear that there exist 4 regions determined by the strength of radial electric field: 1) the region of linear m=2 mode excitation, 2) the region of simultaneously excited m=1 and m=2 modes, 3) the region of alternatively appearance of m=1 and m=2 modes, 4) the region that m=1 becomes sawtooth oscillation and the plasma disruption takes place. The region 4) considerably resembles the Tokamak behavior of the tearing instability and the plasma disruption. Our data show the importance of the nonlinear developing process where m=1 mode overcomes m=2 mode and induces the plasma disruption.

通过这一研究，我们获得了较详细的关于旋转角速度变化引起的等离子体破坏的非线性发展过程的数据，这些数据是去年初步获得的。为了验证利用去年研制的多探头观测等离子体密度在垂直于磁场平面上的行为的方法，我们将该方法应用于漂移波，并成功地获得了漂移波涡旋随漂移波速度漂移的初步数据。因此，我们可以证明该二维测量系统的高能力。遗憾的是，虽然我们观察到等离子体以旋转角速度的剪切方式扩散，但我们无法成功地观察到锯齿状振荡和等离子体破坏的二维观测。这是因为对锯齿振荡和等离子体破坏的控制不足，导致了再现性的缺乏。现在，我们正在努力改善这一点。因此，我们利用示波器观测到的不是二维等高线数据，而是多探头的直接数据，并详细讨论了锯齿振荡与等离子体破坏之间的关系。研究结果表明，由径向电场强度决定的区域有4个：1)m=2模式线性激发区域，2)m=1和m=2模式同时激发区域，3)m=1和m=2模式交替出现区域，4)m=1变为锯齿振荡并发生等离子体破坏的区域。该区域4)非常类似于托卡马克的撕裂不稳定性和等离子体破坏行为。我们的数据显示了非线性发展过程的重要性，其中m=1模式克服了m=2模式并引起等离子体破坏。