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Space‐charge‐limited current of vacuum arc thruster
Author(s) -
Zhang Tianping,
Chang Lei,
Hu Xinyue,
Wang Runlong,
Zhang Huijie,
Wu Xianming,
Sun Xinfeng,
Hu Ning
Publication year - 2020
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/ctpp.201900163
Subject(s) - vacuum arc , current (fluid) , space charge , arc (geometry) , cathode , physics , current density , voltage , atomic physics , mechanics , anode , computational physics , materials science , electron , plasma , electrical engineering , electrode , geometry , nuclear physics , quantum mechanics , mathematics , thermodynamics , engineering
To optimize thrust performance, the expression of space‐charge‐limited current for vacuum arc thruster is derived from Poisson's equation. The commonly used ring‐type and coaxial‐type vacuum arc thrusters are simplified to the equivalent current sheet in planar geometry and cylindrical capacitor, respectively, for this calculation. Both the spatial distribution and peak magnitude of space‐charge‐limited current are given explicitly, together with their dependences on gap distance, applied voltage, charge number, and ion mass. For typical experimental parameters of the vacuum arc thruster, it is shown that the maximum current density drops significantly when the gap distance becomes large and grows when the applied voltage increases; moreover, a cathode material of lower atomic weight yields a higher current density. The expressions of total current for these two types of vacuum arc thruster are also presented. This work, to our best knowledge, is the first application of space‐charge‐limited current to the vacuum arc thruster and practically very interesting for engineering design.