Mechanism Analysis of the Effect of Axial Magnetic Field on Low Pressure Glow Discharge

The effect of axial magnetic field on glow discharge parameters at low pressure is studied in this article. First, Paschen’s law under axial magnetic field is modified. The results show that under the same conditions, the magnetic field will increase the breakdown voltage of glow discharge. The experimental results are consistent with the theoretical analysis, but the experimental value is higher than the theoretical value. Second, the physical model of parallel field glow discharge is established, and the plasma density of glow discharge under different pressure, discharge spacing, and magnetic field is studied. The results show that the plasma density increases with the increase in magnetic field at low pressure; at high pressure, the larger the magnetic field, the smaller the plasma density. At the same position, the plasma density increases with the increase in discharge spacing in weak magnetic field, and it decreases with the increase in discharge spacing in strong magnetic field. When the surface area of the magnet is only 20% of the surface area of the anode and cathode, the radial nonuniformity of the magnetic field makes the plasma density reach the maximum when the radial $r =0$ .