中国物理B ›› 2010, Vol. 19 ›› Issue (7): 75207-075207.doi: 10.1088/1674-1056/19/7/075207
刘国治, 杨占峰
Liu Guo-Zhi (刘国治), Yang Zhan-Feng (杨占峰)
摘要: A two-dimensional solution of space-charge-limiting current for a high current vacuum diode with a spherical cathode is presented. The relation between space-charge-limiting current and electric field enhancement factor at the cathode surface for the diode with a curved surface cathode is also discussed. It is shown that compared with the current given by the conventional Child—Langmuir law, which describes the one-dimensional space-charege-limiting current, the two-dimensional space-charge-limiting current in such a diode is enhanced due to the electric-field enhancement along the cathode surface. Among practical parameter ranges, enhancement factor ηb approximately satisfies ηb ≈ Aβn, where β is the electric field enhancement factor at the cathode surface, and n is a constant between 1 and 2, which is confirmed to be universal for the diodes with curved surface cathodes.
中图分类号: (Magnetohydrodynamic generators and thermionic convertors; plasma diodes)