Non-inductive plasma initiation and plasma current ramp-up on the TST-2 spherical tokamak
Non-inductive plasma initiation and plasma current ramp-up on the TST-2 spherical tokamak
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TST-2 球形托卡马克上的非感应等离子体引发和等离子体电流斜坡上升
DOI：
10.1088/0029-5515/53/6/063006
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
R. Shino,
中科院分区：
文献类型：
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作者：
Y. Takase;A. Ejiri;H. Kakuda;T. Oosako;T. Shinya;T.Wakatsuki;T. Ambo;H. Furui;T. Hashimoto;J. Hiratsuka;H. Kasahara;K. Kato;R. Kumazawa;C.P. Moeller;T. Mutoh;A. Nakanishi;Y. Nagashima;K. Saito;T. Sakamoto;T. Seki;M. Sonehara;R. Shino,
在TST-2装置上研究了低杂波（LH）频率波对球形托卡马克（ST）等离子体电流（Ip）的启动。低电流（101 kA）ST配置可由宽频率范围（TST-2中为21 MHz-8.2 GHz）内的波形成，但进一步I p斜升（至101 kA）对LH频率范围内的波最有效。在200 MHz的快波（FW）极化下，用60 kW的净RF功率P RF实现了I p斜升到15 kA。X射线测量结果表明，光子通量和温度较高的方向相反的IP，一致的电子加速由一个单向的RF波。有证据表明，LH波被激发的FW的非线性，根据由磁探针测量的频谱。电感梳状天线和介质加载的波导阵列（“格栅”）天线，获得类似的效率的IP斜升，并观察到的趋势，电流驱动效率增加等离子体电流和环向场。在格栅天线的操作期间，波矢量分量由磁探针阵列测量。根据FW和LH波的离散度关系，结果在定性上与预期一致。已经开发了一个电容耦合梳状线天线，以改善与等离子体的耦合和激发的LH波的波数谱，并将于2013年进行测试。
Plasma current (I p) start-up in a spherical tokamak (ST) by waves in the lower-hybrid (LH) frequency range was investigated on TST-2. A low current (∼ 1 kA) ST configuration can be formed by waves over a broad frequency range (21 MHz–8.2 GHz in TST-2), but further I p ramp-up (to∼ 10 kA) is most efficient with waves in the LH frequency range. I p ramp-up to 15 kA was achieved with 60 kW of net RF power P RF in the fast wave (FW) polarization at 200 MHz excited by the inductively coupled combline antenna. X-ray measurements showed that the photon flux and temperature are higher in the direction opposite to I p, consistent with acceleration of electrons by a uni-directional RF wave. There is evidence that the LH wave is excited nonlinearly by the FW, based on the frequency spectra measured by magnetic probes. Similar efficiencies of I p ramp-up were obtained with the inductive combline antenna and the dielectric-loaded waveguide array ('grill') antenna, and tendencies for the current drive efficiency to increase with plasma current and toroidal field were observed. During operation of the grill antenna, wavevector components were measured by an array of magnetic probes. Results were qualitatively consistent with expectations based on dispersion relations for the FW and the LH wave. A capacitively coupled combline antenna has been developed to improve coupling to the plasma and the wavenumber spectrum of the excited LH wave, and will be tested in 2013.