Slower impedance collapse with hot anode and enhanced emission cathode

Author

Pereira, N.R. ; Fisher, A.

Author_Institution

Ecopulse Inc., Springfield, VA, USA

Volume

27

Issue

4

fYear

1999

fDate

8/1/1999 12:00:00 AM

Firstpage

1169

Lastpage

1174

Abstract

As most high power diodes, our nominally 1 kA and 300 kV diode shorts out during the pulse. This so-called impedance collapse can be affected by the anode temperature and by surface conditions on the carbon fiber cathode. With the tantalum anode at room temperature, impedance collapse occurs after about 200 ns. Collapse takes 100 ns longer when the anode is hot, 800-1200 K. Covering the carbon fibers in the cathode with cesium iodide delays collapse by another 100 ns. These observations are consistent with pre-shot removal of loosely bound adsorbates off the anode by the high temperature, and with easier electron emission from the cathode out of smaller, less violent explosive emission spots

Keywords

anodes; cathodes; discharges (electric); plasma diodes; plasma production; plasma transport processes; space charge; 1 kA; 100 ns; 200 ns; 300 kV; 800 to 1200 K; C; C fiber cathode; CsI; Ta; Ta anode; anode temperature; electron emission; enhanced emission cathode; explosive emission spots; high power diodes; hot anode; impedance collapse; loosely bound adsorbates; pre-shot removal; room temperature; surface conditions; Anodes; Cathodes; Diodes; Electrodes; Electron emission; Plasma density; Plasma temperature; Space charge; Surface impedance; Voltage;

fLanguage

English

Journal_Title

Plasma Science, IEEE Transactions on

Publisher

ieee

ISSN

0093-3813

Type

jour

DOI

10.1109/27.782297

Filename

782297