Scattering of High Energy Ions due to Spontaneously Excited Alfven Waves

在伽马10串列反射镜中，当离子回旋频率范围（ICRF）加热时，产生具有强温度各向异性的等离子体。由于等离子体的强温度各向异性，阿尔芬离子回旋（AIC）模在等离子体中被自发激发。本文研究了Alfven波的激发机制以及高能离子与自发激发波的关联。主要研究结果如下：1.我们观察到，在比理论预测的参量低一个量级的参量范围内，伽马10串列镜中的AIC模是不稳定的。AIC模被激发为在轴向方向上具有边界的本征模。边界由等离子体压力决定.我们建立了一个诊断系统，通过注入低功率ICRF波来评估等离子体参数。测量了天线的载荷和激励波的振幅。很明显，天线负载降低，并且波在AIC模式的频率范围内以正增长率共振激发。这表明AIC模式首先由外部天线激发。我们用半导体探测器建立了另一个诊断系统，测量高能离子在中央池中的俯仰角分布。很明显，高能离子的俯仰角分布是由ICRF波的加热和自发激发波的散射作用决定的.端部损失离子与中央细胞中AIC模的振幅有很强的相关性。实验表明，在中心单元中产生的热离子被散射到损耗锥中，并通过AIC模式损耗到末端。

In the GAMMA 10 tandem mirror, plasmas with the strong temperature anisotropy are created when the ion cyclotron range of frequency (ICRF) heating is applied. The Alfven ion cyclotron (AIC) modes are spontaneously excited in the plasma due to such the strong temperature anisotropy. In this research, we studied the excitation mechanism of the Alfven waves and the correlation between high energy ions and spontaneously excited waves. Obtained results are summarized as followings ;1. The AIC modes in the GAMMA 10 tandem mirror are observed to be unstable in the parameter range below an order of magunitude lower than the parameters predicted by the theory. The AIC modes are excited as eigenmodes which have the boundary in the axial direction. The boundary is determined by the plasma pressure.2. We constructed a diagnostics system to evaluate the plasma parameters by injecting low power ICRF waves. The antenna loading and the amplitude of the excited waves are measured. It becomes clear the antenna loading decreases and the waves are resonantly excited in the frequency range of the AIC modes with a positive growth rate. This indicates the AIC modes are firstly excited by the external antenna.3. We constructed another diagnostic system with a semi-conductor detector to measure the pitch angle distribution of high energy ions in the central cell. It becomes clear the pitch angle distribution of high energy ions is determined from the effects of the heating by ICRF waves and the scattering by spontaneously excited waves.4. The end loss ions have strong correlation with the amplitude of the AIC mode in the central cell. It becomes clear experimentally the hot ions created in the central cell are scattered into the loss cone and lossed to the end by the AIC modes.