Particle-in-Cell Simulations of Ion Beam Properties Produced From a Planar Pinched-Beam Diode
Document Type
Article
Publication Date
1-2023
Abstract
Particle-in-cell simulations of a 1.6-MV, 400-kA, and 50-ns planar pinched-beam diode show that ion current and efficiency increase as anodes are made longer and thinner. At the length limit of this investigation, we observe efficiencies reaching 75% with approximately 300 kA of ion current. In general, making anodes longer and thicker improves uniformity but reduces fluence. However, there is a limit to uniformity improvement as thicker anodes display spotty ion emission behavior. Thinner anodes can generate higher fluences than thicker anodes for a portion of the anode length due to electron reflexing. However, uniformity is not improved and the fluence drops substantially in a portion of the anode due to virtual cathode expansion in the diode. Among all simulations, the best balance of fluence and uniformity was for an 8-cm-long, 400- μm -thick anode, which provided a fluence of 10 cal/cm2 over 100 cm2 with a uniformity of ±25%. Thinner anodes also show a broader ion energy distribution than thicker anodes, likely due to ions coupling to an oscillating electric field associated with an instability in the diode particle flow.
Source Publication
IEEE Transactions on Plasma Science (ISSN 0093-3813, 1939-9375)
Recommended Citation
Foster, J. C., McClory, J. W., Swanekamp, S. B., & Ottinger, P. F. (2023). Particle-in-Cell Simulations of Ion Beam Properties Produced From a Planar Pinched-Beam Diode. IEEE Transactions on Plasma Science, 51(1), 90–103. https://doi.org/10.1109/TPS.2022.3229285
Comments
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Co-author Lt Col Jesse Foster was an AFIT PhD student at the time of this publication.