在高谐波快波加热期间TST-2中一个新的参量衰变不稳定性分支的探测。

Detection of a new parametric decay instability branch in TST-2 during high harmonic fast wave heating.

作者信息

Adachi Y, Ejiri A, Takase Y, Watanabe O, Oosako T, Tojo H, Kainaga S, Masuda T, Sasaki M, Sugiyama J, Yamaguchi T

机构信息

The University of Tokyo, Kashiwa 277-8561, Japan.

出版信息

Rev Sci Instrum. 2008 Oct;79(10):10F507. doi: 10.1063/1.2955574.

DOI:10.1063/1.2955574

PMID:19044652

Abstract

Parametric decay instability (PDI) is often observed in the TST-2 spherical tokamak during high harmonic fast wave heating by rf pickup probes. The frequency spectrum exhibits lower and upper sideband peaks in addition to the pump wave at f(0)=21 MHz. Two types of PDI are observed. One is the well-known decay into the ion-cyclotron quasimode (nf(ci)) and the ion Bernstein wave (f(0)-nf(ci)). The other is a newly found decay with the sideband frequency between f(0) and f(0)-f(ci). The frequency difference between this sideband and the pump increases in proportion to B(t). Moreover, high-speed visible light measuring systems with photomultiplier tubes or hybrid photodetectors viewing the plasma core detected oscillation of light emission at around f(0).

摘要

在TST - 2球形托卡马克中，通过射频拾取探针进行高谐波快波加热时，经常观察到参量衰变不稳定性（PDI）。频谱除了在f(0)=21 MHz处的泵浦波外，还呈现出较低和较高的边带峰值。观察到两种类型的PDI。一种是众所周知的衰变为离子回旋准模（nf(ci)）和离子伯恩斯坦波（f(0)-nf(ci)）。另一种是新发现的衰变，其边带频率在f(0)和f(0)-f(ci)之间。该边带与泵浦之间的频率差与B(t)成比例增加。此外，使用光电倍增管或混合光电探测器的高速可见光测量系统观察等离子体核心，检测到在f(0)附近的光发射振荡。