MM-4U中等离子体约束位形和不稳定性的实验研究

给出了MM-4u中等离子体约束位形和不稳定性的实验结果。测得的等离子体电位轴向分布表明,该装置中能够建立起负电位轴对称串级镜约束位形;测得的密度分布与电位分布有相似形式。初步探索了等离子体参数与工程参数的关系。实验还发现在低密度情况下存在低频振荡。通过对振荡信号进行线性相关分析,根据扰动的振荡和传播特性,推断出这种振荡为离子声不稳性。不稳定性产生的可能机制是由于电子束穿过低密度本底等离子体的漂移速度超过离子声速而激发起来的。关键词：

EXPERIMENTS ON INSTABILITY AND POTENTIAL CON- FINEMENT CONFIGURATION IN MM-4U TANDEM MIRROR

Experimental results on plasma instability and potential confinement configuration in MM-4U tandem mirror are presented. The measured axial potential profile shows that the axisymmetric negative plasma potential tandem mirror confinement configuration has been established; the obtained plasma density profile is similar to the potential profile. The relationships between the plasma parameters and the eng-neering parameters have also been studied prelimilarily. The low frequency instability was observed at low plasma density in the central cell. By means of the linear spectral analysis techniques, the instability mode has been determined. It is suggested that the instability is excited in the low density plasma when the electron beam drift velocities exceed the ion acoustic speed.