Space charge limited current for bipolar flow in a crossed-field vacuum gap
In this paper, a numerical iteration approach is proposed to make an investigation of the influence of a transverse magnetic field on the space charge limited bipolar flow in a planar vacuum diode. By employing the method, the unknown limiting current density and potential distribution can be simult...
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Published in | Vacuum Vol. 196; p. 110744 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Elsevier Ltd
01.02.2022
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Subjects | |
Online Access | Get full text |
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Summary: | In this paper, a numerical iteration approach is proposed to make an investigation of the influence of a transverse magnetic field on the space charge limited bipolar flow in a planar vacuum diode. By employing the method, the unknown limiting current density and potential distribution can be simultaneously determined. Considering a planar ion vacuum diode with a transverse magnetic field B parallel to the electrodes surface, we investigated the limiting current density as a function of B. Numerical calculations show that the limiting current density of the crossed-field vacuum diode may be approximately given by Je=JCL[a(B/BH)b+F], where JCL is the CL law and BH the Hull cutoff magnetic field, and a and b are the function of the ion current density, respectively. The physical meaning of F may be interpreted as the 1D current density enhancement factor due to the effect of ions for B=0. In the absence of ions, the limiting current solution is recovered in a crossed-field vacuum gap. |
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ISSN: | 0042-207X 1879-2715 |
DOI: | 10.1016/j.vacuum.2021.110744 |