Title :
Explosive emission and gap closure from a relativistic electron beam diode
Author :
Coleman, J.E. ; Moir, D.C. ; Ekdahl, C.A. ; Johnson, J.B. ; McCuistian, B.T. ; Crawford, M.T.
Author_Institution :
Los Alamos Nat. Lab., Los Alamos, NM, USA
Abstract :
Explosive emission cathode studies are currently being conducted on a high power relativistic electron beam diode. A black velvet cathode is driven with a 75 Ohm graded transmission line, which provides a 3.8 MV, 80 ns (FWHM) pulse across a fixed A-K gap of 17.8 cm. Cathode sizes range from 1.9-7 cm with space-charge limited currents of 0.26-3 kA. The principal objective of these experiments is to quantify the current emission limits and the dynamics of the gap closure process. A qualitative comparison of experimental and calculated results are presented, which included the I-V relationship, impedance and perveance curves, plasma expansion velocity, and the time-resolved light emission on the surface of the cathode.
Keywords :
cathodes; diodes; electron beam effects; space-charge limited devices; transmission lines; FWHM pulse; I-V relationship; black velvet cathode; cathode sizes; cathode surface; current 0.26 kA to 3 kA; current emission limits; explosive emission cathode; fixed A-K gap; gap closure process; graded transmission line; high power relativistic electron beam diode; impedance curves; perveance curves; plasma expansion; resistance 72 ohm; size 1.9 cm to 7 cm; size 17.8 cm; space-charge limited currents; time 80 ns; time-resolved light emission; voltage 3.8 MV; Cathodes; Current measurement; Explosives; Face; Impedance; Plasma measurements; Voltage measurement;
Conference_Titel :
Pulsed Power Conference (PPC), 2013 19th IEEE
Conference_Location :
San Francisco, CA
DOI :
10.1109/PPC.2013.6627454
