RF Heating of Spherical Tokamak Plasmas

球形托卡马克（ST）可以在小型装置中产生高性能的等离子体。ST最重要的问题是等离子体电流斜坡和非感应方式的维护。离子回旋频率范围内的高次谐波快波（HHFW）在具有很高介电常数的ST等离子体中具有良好的传播和吸收特性。本研究的目的是研究高频波的激发、传播和吸收。产生和维持一个足够高密度的等离子体以激发HHFW和足够高的电子温度以吸收HHFW是必不可少的。TST-2装置是为此目的而构造的，并且实现了具有所需密度和温度的等离子体。波激励采用梳状线行波天线。在优化的基础上，利用样机天线，六单元天线的实验制作。用安装在真空室壁上不同位置的磁探针进行了波检测， 关于我们 等离子体负载电阻随着等离子体的发展而变化，并且当等离子体电流达到峰值时达到最大值，正如预期的那样。在环的内侧（高场侧），环向方向上的非均匀性较弱（约5dB），并且垂直非均匀性甚至更弱。相比之下，外侧探测器检测到的信号比内侧探测器强10- 15 dB。这些结果与ASK/WM全波程序一致。此外，在1 kW的电子回旋波作用下，获得了高达1.2kA的等离子体电流。在垂直方向上存在镜像磁场配置的情况下，由电离产生的电子被镜像场捕获，并且电流可以通过它们的钻孔运动流动，并且随后压力驱动电流可以流动。如果等离子体可以形成，并且等离子体电流可以如这些实验中所示通过RF波斜升，则中心螺线管变得不必要，并且ST作为聚变反应堆的吸引力大大增强。少

The Spherical Tokamak (ST) can produce high performance plasmas in a small device. The most important issue for the ST is plasma current rampup and maintenance by noninductive means. The high-harmonic fast wave (HHFW) in the ion-cyclotron frequency range has good propagation and absorption characteristics in ST plasmas with very high dielectric constants. the aim of this study is to study excitation, propagation, and absorption of HHFW. It is indispensable to produce and, maintain a plasma with high enough density for HHFW excitation and high enough electron temperature for its absorption. The TST-2 device was constructed for this purpose and plasmas with the required density and temperature were achieved. A traveling wave antenna called the combline antenna was adopted for wave excitation. Based on optimization using mockup antennas, a six-element antenna was fabricated for the experiment. Magnetic probes installed at various locations on the vacuum vessel wall were used for wave dete … More ction- The plasma loading resistance varied as the plasma evolved, and reached a maximum when the plasma current reached a peak, as expected. On the inboard side (high field side) of the torus, the nonuniformity in the toroidal direction is weak (about 5dB) and the vertical nonuniformity was even weaker. In contrast, the outboard probes detected stronger signals by 10-15dB compared to inboard probes. These results are consistent with the TASK/WM full-wave code. In addition, plasma currents of up to 1.2kAwere achieved with 1kW of electron cyclotron wave. In the presence of a mirror magnetic field configuration in the vertical direction, electrons produced by ionization are trapped by the mirror field and a current can flow by their drill: motion, and subsequently pressure driven currents can flow. If the plasma can be formed and the plasma current can be ramped up by RF waves as shown in these experiments, the central solenoid becomes unnecessary and the attractiveness of the ST as a fusion reactor is greatly enhanced. Less