Model for relaxation oscillations in a helicon discharge
Model for relaxation oscillations in a helicon discharge
复制标题
螺旋放电中的弛豫振荡模型
DOI：
10.1063/1.873419
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
R. Boswell
中科院分区：
文献类型：
--
作者：
A. Degeling;T. Sheridan;R. Boswell
大体积螺旋等离子体实验中的弛豫振荡[j]。W. Boswell和R. K. Porteous，苹果。理论物理。Lett. 50,1130(1987)]被建模。这些振荡周期为几毫秒，并被确定为低密度感应放电和高密度螺旋波放电之间的过渡。在模型中，假设模态转换是由源区中性密度的变化触发的。中性密度由于离子泵送增加的电离作用而降低，而由于源室从更大的扩散室重新填充而增加。该系统使用两个耦合的非线性常微分方程来描述源室中的中性密度和等离子体密度。由感应耦合场引起的电离和由相速度接近电离阈值电子速度的螺旋波加速的电子引起的电离。
Relaxation oscillations observed in the large-volume, helicon plasma experiment WOMBAT (Waves on Magnetized Beams and Turbulence) [R. W. Boswell and R. K. Porteous, Appl. Phys. Lett. 50, 1130 (1987)] are modeled. These oscillations have a period of several milliseconds and have been identified as transitions between a low-density, inductive discharge and a high-density, helicon-wave discharge. In the model, it is assumed that the mode transitions are triggered by variations in the neutral density in the source region. The neutral density decreases due to ionization augmented by ion pumping and increases due to refilling of the source chamber from the much larger diffusion chamber. The system is modeled using two, coupled, nonlinear, ordinary differential equations that describe the neutral and plasma densities in the source chamber. Ionization by inductively-coupled fields and ionization due to electrons accelerated by helicon waves with phase velocities near the threshold electron velocity for ionization...