Measurement and interpretation of current transmission in a crossed-field diode below cutoff

Vanderberg, B.H.; Eninger, J.E.

doi:10.1063/1.872567

Cited by 5 publications

(1 citation statement)

References 15 publications

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“…There are other recent studies of cycloidal flow in a crossed-field gap. [8][9][10][11] While singleparticle orbits have been found unstable in nonorthogonal E and B due to a gradient in E, 12 the collapse of the cycloidal flow analyzed in the present paper is due to a very different mechanism.…”

Section: Introductionmentioning

confidence: 55%

Collapse of cycloidal electron flows induced by misalignments in a magnetically insulated diode

1998

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The effect of a slight misalignment in the magnetic field on a magnetically insulated diode is investigated. It is found that a slight tilt in the magnetic field, with a minute component along the dc electric field, completely destabilizes the cycloidal electron flow in the crossed-field gap. The final state consists of the classical Brillouin flow superimposed by a turbulent background, together with a slow electron drift across the gap. This disruption of the cycloidal flow is quite insensitive to the emission current density, and is due to the accumulation of space charge in the gap caused by the magnetic misalignment. This result was obtained from a one-dimensional simulation code. It reinforces the notion that the turbulent, near Brillouin-like states are generic in ALL vacuum crossed-field devices.

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Section: Introductionmentioning

confidence: 55%

Collapse of cycloidal electron flows induced by misalignments in a magnetically insulated diode

1998

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Influence of electrons reflected from a target on the operation of triode-type electron sources

Engelko

Kuznetsov

Viazmenova

et al. 2000

Journal of Applied Physics

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An external magnetic field between the electron source and a target causes the reflected electrons to move along the magnetic force lines towards the source region. There they get reflected back to the target by the electric field of the source. These electrons distort the electric field in the source region, and change the source’s operational parameters. Penetration of reflected electrons back into the source region reduces essentially the space charge limited emission current density of a cathode and the minimum current density to form a potential minimum and a virtual cathode. How much the emission current density decreases depends on the target material’s atomic number, Z, which determines the reflection coefficient and the energy spectrum of the reflected electrons. The calculations are in good agreement with experimental data. The analysis shows that reflected electrons must be considered for a correct calculation of the beam parameters at the target for the distribution of the energy density deposited into the target, and for a better understanding of the electron source operation.

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Reduction of crossed-field diode transmitted current due to anode secondary emission

Gopinath

Vanderberg

1998

Physics of Plasmas

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The limiting current theory for planar crossed-field diodes has long been studied extensively for various emission energies and temperatures. However, experimental measurements of transmitted current have shown significant departure from theory. This paper attempts to explain the reduction in transmitted current from that expected in theory in terms of secondary electron emission created by electrons hitting the anode. It is proposed that the presence of the secondary electrons increases the charge density in the gap, thereby reducing the amount of current transmitted. A detailed secondary emission model is implemented in a particle-in-cell code to study current reduction. The effect of secondary electrons on charge density, and on the resultant electric field and potential is also presented.

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Measurement and interpretation of current transmission in a crossed-field diode below cutoff

Cited by 5 publications

References 15 publications

Collapse of cycloidal electron flows induced by misalignments in a magnetically insulated diode

Collapse of cycloidal electron flows induced by misalignments in a magnetically insulated diode

Influence of electrons reflected from a target on the operation of triode-type electron sources

Reduction of crossed-field diode transmitted current due to anode secondary emission

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