Current loss of magnetically insulated coaxial diode with cathode negative ion  

作　　者：朱丹妮 张军 钟辉煌 高景明 白珍 

机构地区：[1]College of Optoelectronic Science and Engineering, National University of Defense Technology

出　　处：《Chinese Physics B》2018年第2期261-266,共6页中国物理B（英文版）

摘　　要：Current loss without an obvious impedance collapse in the magnetically insulated coaxial diode （MICD） is studied through experiment and particle-in-cell （PIC） simulation when the guiding magnetic field is strong enough. Cathode nega- tive ions are clarified to be the predominant reason for it. Theoretical analysis and simulation both indicate that the velocity of the negative ion reaches up to 1 cm/ns due to the space potential between the anode and cathode gap （A-C gap）. Accord- ingly, instead of the reverse current loss and the parasitic current loss, the negative ion loss appears during the whole pulse. The negative ion current loss is determined by its ionization production rate. It increases with diode voltage increasing. The smaller space charge effect caused by the beam thickening and the weaker radial restriction both promote the negative ion production under a lower magnetic field. Therefore, as the magnetic field increases, the current loss gradually decreases until the beam thickening nearly stops.Current loss without an obvious impedance collapse in the magnetically insulated coaxial diode （MICD） is studied through experiment and particle-in-cell （PIC） simulation when the guiding magnetic field is strong enough. Cathode nega- tive ions are clarified to be the predominant reason for it. Theoretical analysis and simulation both indicate that the velocity of the negative ion reaches up to 1 cm/ns due to the space potential between the anode and cathode gap （A-C gap）. Accord- ingly, instead of the reverse current loss and the parasitic current loss, the negative ion loss appears during the whole pulse. The negative ion current loss is determined by its ionization production rate. It increases with diode voltage increasing. The smaller space charge effect caused by the beam thickening and the weaker radial restriction both promote the negative ion production under a lower magnetic field. Therefore, as the magnetic field increases, the current loss gradually decreases until the beam thickening nearly stops.

关 键 词：magnetically insulated coaxial diode （MICD） cathode plasma negative ion current loss 

分 类 号：O441[理学—电磁学]