Analysis of the current-diffusive ballooning mode

Posted by Pixel-Rabbit on Friday, August 5, 2022

Analysis of the current-diffusive ballooning mode

M. Yagi, K. Itoh, S.-I. Itoh, et al.Physics of Fluids B: Plasma Physics 5, 3702 (1993); 分析了托卡马克位形下等离子体的电流耗散型气球模 (current-diffusive ballooning mode)
investigated the linear stability of the current-diffusive ballooning mode (A mode) in the large aspect ratio tokamak with circular cross section 大环径比圆截面托卡马克 这种模式由电流耗散(如电子粘滞)所解稳,由热导率和离子粘滞致稳。此外, ballooning mode instability 的增长率随电阻率的增大而变大。

Strong ballooning limit

first, search the mode which is localized around $\theta \approx0$, in the limit of $1<s, \rho<s, $ 最终通过一些极限条件,将方程化简

Stabilization by the viscosity and thermal conduction on A mode

  1. 理论分析 采取 strong ballooning limit 条件,获得方程: $\hat{\chi}=\chi n^2q^2,\chi=\frac{\tau_{PA}\chi_{\perp}}{r_{mn}^2}$ 使用 WKB method 得到增长率: 表明,增长率随$\mu,\chi$增大而减小,$\mu$是 ion viscosity
  2. 数值模拟

conclusion

电流扩散率驱动高温等离子体的气球模,而电阻率驱动低温等离子体的气球模。有限的电子惯性和电子粘度是电流扩散率的来源。研究了几何因素(如环向性、磁剪切和q值)以及压强梯度的影响