不同压强时等离子体宏观不稳定性的数值模拟

Simulation of Plasma Macroscopic Instability at Different Pressures

为了数值模拟不同等离子体压强和不同角向模数时,磁流体不稳定性的演化规律,本文通过傅里叶变换,将理想磁流体方程组转化为两个一阶微分方程。通过求解这两个微分方程,可以求解不稳定性的增长率。数值模拟结果表明:等离子体压强均匀时,不稳定性的增长率随角向模数的增大而减小;等离子体压强是半径的函数时,不稳定性的增长率随角向模数的增大而增大,这种差异是由等离子体压强梯度引起的。所得到的数值模拟结果可用于分析直圆柱托卡马克或等离子体天线中磁流体的宏观不稳定性。

We addressed the evolution of the plasma magneto-hydmdynarnic（MHD）instability at different pressures and with different poloidal mode numbers. The ideal MHD equations were first converted into two sets of 1st order differ- ential equation by Fourier transformation, then, the growth rate of the instability was calculated by solving the two differen- tial equations. The simulated results show that at a uniformly distributed plasma pressure, the growth rate decreases with an increase of the poloidal mode number; whereas at a cylindrically distributed plasma pressure, the growth rate increases with an increase of the poloidal mode number. The gradient of the plasma pressure possibly results in the two different variation modes of the growth rate. We suggest that the simulated results may be of much technological interest in analysis of the macroscopic instability of MHD in cylindrical tokomak and plasma antenna.