Mode Conversion of Alfven Waves and Microinstabilities in a Non-uniform Magnetic Field

非均匀磁场中阿尔文波的模式转换和微观不稳定性

基本信息

批准号：
02452270
负责人：
INUTAKE Masaaki
金额：
$ 2.82万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

The quadrupole anchor cells are located between an axisymmetric central cell and axisymmetric plug /barrier cells in the GAMMA10 tandem mirror. There are recircularizing-transition regions on both sides of the anchor cell, where The magnetic flux tube has an elliptical cross section. ICRF antennas, of which azimuthal mode m can be controlled, are installed near both ends of the central cell.It is found from wave-field measurements that a right-circularly polarized, m=+l fast Alfven wave excited in the central cell is efficiently mode converted to a left-circularly-polarized, m=-l slow Alfven wave in the anchor cell. As a physical mechanism is proposed a model that the mode conversion is brought about by a resonant mode coupling caused by the elliptical (m=<plus-minus>/-2) modulation of the flux tube in The quadruple transition region. Coupled-Alfven-wave equations are theoretically formulated, and are analytically solved under The assumption of a weakly-modulated, periodic quadruple fi … More eld. Theoretical results validate the above conversion model and tell that fast and slow Alfven waves do not couple with each other without the quadruple component and propagate independently. Resonant heating of the anchor ions by the mode-converted slow wave is directly confirmed with diamagnetic loops. It is found that the anchor ions are heated by the fast wave, not by the slow wave excited in the central cell and thus the conversion efficiency should be very high. Moreover, a stability boundary for the flute interchange mode has been identified by varying the anchor beta value, clearly demonstrating the validity of the averaged minimum-B stabilization of a flute mode in a tandem mirroA microscopic instability, Alfven-ion-cyclotron (AIC) mode, expected in a high beta plasma with pressure anisotropy, has been identified in the ICRF-heaLed central-cell plasmas. Observed magnetic field fluctuations strongly depend on the temperature anisotropy and the beta value. Relaxation of the pressure anisotropy due to the AIC mode fluctuations and the concurrent increase of high energy ion loss into the mirror loss cone have been observed. Less

四极锚式细胞位于轴对称性细胞之间，轴对称插头 /屏障细胞是锚固细胞的循环式转换区域，将其控制在两个ED附近=+l在中央电池中的快速alfvents有效地转换为左圆形的，m = -l慢慢的锚固细胞中的Alfven波是由Elipture引起的谐振模式（M = <）加上 - >/ - 2）在四型转变调节中的通量管的调制。 Alfven E独立，通过改变锚点β值的稳定边界已经确定了笛子互换模式的稳定边界，清楚地证明了长笛mirroa微观Instabity lotron（AIC）模式的平均最小B稳定性的有效性，预计在高βPolasma中具有高压力各向异性已成为ICRF愈合的中央血浆，观察到的磁场很大程度上取决于温度各向异性和beta值。少了