It is shown that ion current is a power function of pressure,independently of the magnetic field strength, providing the magnetic field is over a critical value.

• 分析表明，当磁场强度大于某一临界值时，磁控放电的离子电流与磁场强度无关；离子电流是压强的幂函数，且与所测真空器件电极的表面状况和几何结构有关。