纵向磁场对真空电弧微观特性影响的研究

纵向磁场作用下真空电弧等离子体的微观参数变化趋势对于真空电弧的发展和能量变化有着重要的意义。文中基于气体动力学的漂移扩散方程,耦合电场计算的泊松方程,仿真分析了真空电弧在液态金属桥断裂之后,极间充满了大量的Cu金属蒸气后,到电弧等离子形成的这段非平衡态过程。考虑了真空电弧等离子体中微观电子、离子与金属蒸气分子间的碰撞、重组及粒子的漂移、扩散等复杂变化情况,建立了纵向磁场影响下非平衡态真空电弧的微观模型。数值模拟并分析了不同磁场强度对电弧等离子区微观参数的影响及变化规律。仿真结果表明:随着纵向磁场的增大,阴极与阳极鞘层的电场强度减小,有利于电弧熄灭;同时电极过程减弱,电子和铜离子的数密度均减小,阳极表面的电子温度分布均匀且减小,有利于抑制真空电弧能量的提高。

Study on the Influence of Axial Magnetic Field on the Microscopic Characteristics of Vacuum Arc

The variation of microscopic parameters of vacuum arc plasma under the action of axial magnetic field isof great significance to the development of vacuum arc and energy change. In this paper,a non-equilibrium state mi-cro model for vacuum arc under the action of the axial magnetic field is established based on the drift-diffusion equa-tion of gas dynamics and Poisson equation of the electric field. The non-equilibrium process of vacuum arc which isfrom a large number of Cu metal vapor is filled with the fracture of liquid arc bridge to the formation of arc plasma issimulated. Collision and recombination of microelectronics,ion and metal vapor molecules with each other in vacu-um arc plasma and other complex changes such as drift and diffusion of particles are also considered here. The lawsof the plasma parameters at the function of different magnetic field strength are analyzed. The simulation results showthat the electric field strength of cathode and anode sheath decreases with the increase of the axial magnetic field,which is advantageous for quenching the arc meanwhile the electrode process is weakened and the density of the elec-trons and the copper ions are reduced,and the electron temperature distribution on the anode surface is uniform andreduced,which is helpful to suppress the increase of the vacuum arc energy.