Effects of Partial Suppression of Ion Emission in Moderate Impedance Diodes.
Abstract
Numerical simulations have been completed testing the effects of partial ion emission suppression in 4-5 ohm pulsed power diodes. They were conducted to obtain physical insight into the results of a series of parallel experiments conducted on the Gamble II machine at NRL. A standard axial diode with a 3.0 cm outer radius hollow cathode and an electron reflexing anode foil was found to operate at 1.8 MV and 4.8 ohm with an effective ion efficiency of 0.32. Suppressing ion emission along the anode foil beyond a radius equal to the inner radius of the hollow cathode raised the diode impedance at the same voltage to 6.7 ohm and lowered the effective ion efficiency to 0.29. Decreasing the anode-cathode (A-K) gap from 5.0 mm to 3.5 mm and retaining the same degree of ion emission suppression lowered the impedance again in 4.8 ohm and returned the effective ion efficiency again to 0.32. That efficiency is in good agreement with the experimental findings for the same 3.5-mm gap case but is 0.03-0.07 higher than that experimentally observed for the 5.0-mm gap without ion emission suppression. The discrepancy may be actual or it may be due to a return electron current which masks some of the experimentally observed ion current for that case. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1982
- Accession Number
- ADA121309
Entities
People
- Robert J. Barker
- Shyke A. Goldstein
Organizations
- United States Naval Research Laboratory