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

作为研究的结果，我们得到了去年初步获得的旋转角速度灼烧引起的等离子体扰动的非线性发展过程的更详细的数据。为了验证去年研制的多探头观测垂直于磁场平面上等离子体密度行为的方法，我们将这种方法应用于漂移波，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。由此可见，该二维测量系统具有很高的测量能力。不幸的是，虽然我们观察到了旋转角速度剪切中的等离子体扩散，但未能成功地观察到锯齿振荡和等离子体破裂的二维现象。这是由于不能充分控制锯齿振荡和等离子体破裂而导致的重复性不足。现在，我们正在努力改进这一点。因此，我们用示波器观察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裂的关系。研究结果表明，存在4个由径向电场强度决定的区域：1)线性m=2模激发区，2)同时激发m=1和m=2模的区域，3)m=1和m=2模交替出现的区域，4)m=1的区域变成锯齿振荡，发生等离子体破裂。该区域与撕裂不稳定性和等离子体破裂的托卡马克行为非常相似。我们的数据表明了非线性发展过程的重要性，其中m=1模克服了m=2模并导致了等离子体破裂。

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.