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Title: Non-neutral plasma diode in the presence of a transverse magnetic field

Abstract

An analytical study of the plasma states in non-neutral plasma diodes in the presence of an external transverse magnetic field is presented for an arbitrary neutralization parameter γ. Considerations are restricted to the regime where no electrons are turned around by the magnetic field. The emitter electric field strength E{sub 0} is used as a characteristic function to investigate the existence of solutions depending on the diode length, the applied voltage, the neutralization parameter, and the magnetic field strength. The potential distribution has a wave form for small magnitudes of the external magnetic field, as well as for the case when magnetic field is absent. A new family of solutions appears along with the Bursian ones. On the other hand, as the Larmor radius becomes comparable with the beam Debye length, oscillations in the potential disappear, and only the Bursian branches remain. Unlike the vacuum diode, there are steady state solutions for the negative values of the emitter field strength. As the neutralization parameter (γ) increases, the emitter field strength relating to the SCL (space charge limit) bifurcation point diminishes, and at γ > 1, the value of the emitter's electric field strength at the space charge limit (E{sub 0,SCL}) turns outmore » to be negative.« less

Authors:
;  [1]; ;  [2]
  1. Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India)
  2. Ioffe Institute, St. Petersburg (Russian Federation)
Publication Date:
OSTI Identifier:
22598977
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BIFURCATION; COMPARATIVE EVALUATIONS; DEBYE LENGTH; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTRONS; LARMOR RADIUS; MAGNETIC FIELDS; PLASMA; SPACE CHARGE; STEADY-STATE CONDITIONS; THERMIONIC DIODES; WAVE FORMS

Citation Formats

Pramanik, Sourav, Chakrabarti, Nikhil, Kuznetsov, V. I., and Gerasimenko, A. B. Non-neutral plasma diode in the presence of a transverse magnetic field. United States: N. p., 2016. Web. doi:10.1063/1.4953904.
Pramanik, Sourav, Chakrabarti, Nikhil, Kuznetsov, V. I., & Gerasimenko, A. B. Non-neutral plasma diode in the presence of a transverse magnetic field. United States. doi:10.1063/1.4953904.
Pramanik, Sourav, Chakrabarti, Nikhil, Kuznetsov, V. I., and Gerasimenko, A. B. 2016. "Non-neutral plasma diode in the presence of a transverse magnetic field". United States. doi:10.1063/1.4953904.
@article{osti_22598977,
title = {Non-neutral plasma diode in the presence of a transverse magnetic field},
author = {Pramanik, Sourav and Chakrabarti, Nikhil and Kuznetsov, V. I. and Gerasimenko, A. B.},
abstractNote = {An analytical study of the plasma states in non-neutral plasma diodes in the presence of an external transverse magnetic field is presented for an arbitrary neutralization parameter γ. Considerations are restricted to the regime where no electrons are turned around by the magnetic field. The emitter electric field strength E{sub 0} is used as a characteristic function to investigate the existence of solutions depending on the diode length, the applied voltage, the neutralization parameter, and the magnetic field strength. The potential distribution has a wave form for small magnitudes of the external magnetic field, as well as for the case when magnetic field is absent. A new family of solutions appears along with the Bursian ones. On the other hand, as the Larmor radius becomes comparable with the beam Debye length, oscillations in the potential disappear, and only the Bursian branches remain. Unlike the vacuum diode, there are steady state solutions for the negative values of the emitter field strength. As the neutralization parameter (γ) increases, the emitter field strength relating to the SCL (space charge limit) bifurcation point diminishes, and at γ > 1, the value of the emitter's electric field strength at the space charge limit (E{sub 0,SCL}) turns out to be negative.},
doi = {10.1063/1.4953904},
journal = {Physics of Plasmas},
number = 6,
volume = 23,
place = {United States},
year = 2016,
month = 6
}
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  • The properties of a steady-state planar vacuum diode driven by a cold electron beam have been investigated in the presence of an external transverse magnetic field, employing both the Eulerian and the Lagrangian formalism. With the help of a numerical scheme, the features of the steady-state solutions have been explored in the Eulerian frame, particularly for the case that corresponds to the potential distributions with a virtual cathode. However, exact analytical formulae for the potential and velocity profiles within the inter-electrode region have been derived with the Lagrangian description. In contrast to the previous work [Phys. Plasmas 22, 042110 (2015)],more » here we have emphasized the situation when electrons are reflected back to the emitter by the magnetic field. Both partial and complete reflection of the electrons due to the magnetic field have been taken into account. Using the emitter electric field as a characteristic parameter, steady-state solutions have been evaluated for specific values of diode length, applied voltage, and magnetic field strength. It has been shown that, due to the inclusion of the magnetic field, a new region of non-unique solutions appears. An external magnetic field seems to have a profound effect in controlling fast electronic switches based on the Bursian diode.« less
  • A comprehensive study on the steady states of a planar vacuum diode driven by a cold relativistic electron beam in the presence of an external transverse magnetic field is presented. The regimes, where no electrons are turned around by the external magnetic field and where they are reflected back to the emitter by the magnetic field, are both considered in a generalized way. The problem is solved by two methods: with the Euler and the Lagrange formulation. Taking non-relativistic limit, the solutions are compared with the similar ones which were obtained for the Bursian diode with a non-relativistic electron beammore » in previous work [Pramanik et al., Phys. Plasmas 22, 112108 (2015)]. It is shown that, at a moderate value of the relativistic factor of the injected beam, the region of the ambiguous solutions located to the right of the SCL bifurcation point (space charge limit) in the non-relativistic regime disappears. In addition, the dependencies of the characteristic bifurcation points and the transmitted current on the Larmor frequency as well as on the relativistic factor are explored.« less
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