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Title: Dynamics of ion beam charge neutralization by ferroelectric plasma sources

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4947562· OSTI ID:22599153
; ; ; ;  [1]
  1. Princeton Plasma Physics Laboratory, Princeton University, P.O. Box 451, Princeton, New Jersey 08543 (United States)

Ferroelectric Plasma Sources (FEPSs) can generate plasma that provides effective space-charge neutralization of intense high-perveance ion beams, as has been demonstrated on the Neutralized Drift Compression Experiment NDCX-I and NDCX-II. This article presents experimental results on charge neutralization of a high-perveance 38 keV Ar{sup +} beam by a plasma produced in a FEPS discharge. By comparing the measured beam radius with the envelope model for space-charge expansion, it is shown that a charge neutralization fraction of 98% is attainable with sufficiently dense FEPS plasma. The transverse electrostatic potential of the ion beam is reduced from 15 V before neutralization to 0.3 V, implying that the energy of the neutralizing electrons is below 0.3 eV. Measurements of the time-evolution of beam radius show that near-complete charge neutralization is established ∼5 μs after the driving pulse is applied to the FEPS and can last for 35 μs. It is argued that the duration of neutralization is much longer than a reasonable lifetime of the plasma produced in the sub-μs surface discharge. Measurements of current flow in the driving circuit of the FEPS show the existence of electron emission into vacuum, which lasts for tens of μs after the high voltage pulse is applied. It is argued that the beam is neutralized by the plasma produced by this process and not by a surface discharge plasma that is produced at the instant the high-voltage pulse is applied.

OSTI ID:
22599153
Journal Information:
Physics of Plasmas, Vol. 23, Issue 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English

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Cited By (3)

Amplification due to two-stream instability of self-electric and magnetic fields of an ion beam propagating in background plasma journal May 2018
Electrostatic solitary waves in ion beam neutralization journal May 2019
Amplification due to Two-Stream Instability of Self-Electric and Magnetic Fields of an Ion Beam Propagating in Background Plasma text January 2017