Plasma expansion and fast gap closure in a high power electron beam diode

Journal Article · Fri May 15 04:00:00 EDT 2009 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3129802· OSTI ID:21277107

Roy, Amitava; Menon, R; Mitra, S; Kumar, Senthil; Sharma, Vishnu; Nagesh, K V; Mittal, K C; Chakravarthy, D P ^[1]

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1. Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

High power electron beam generation studies were carried out in a planar diode configuration to investigate the effect of the accelerating gap, diode voltage, and anode-cathode materials on the electrode plasma expansion. The diode voltage has been varied from 145-428 kV, whereas the current density has been varied from 208-2215 A/cm{sup 2} with 100 ns pulse duration. It was found that the diode voltage and current follow the bipolar space-charge limited flow model. The anode and cathode plasma expansion velocities were calculated using the perveance data. The plasma expands at 11 cm/{mu}s for 34 mm anode-cathode gap and the plasma velocity decreases for smaller gaps. It was found that the plasma expansion velocity increases significantly due to the cathode edge contribution and the edge contribution is particularly important during the beginning and the end of the accelerating pulse when the diode voltage and the corresponding electric field are comparatively low. It was also observed that the diode current increased by a factor of 3 when anode material was released into the accelerating gap due to the electron beam bombardment.

• OSTI ID: 21277107
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 5 Vol. 16; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANODES
BEAM-PLASMA SYSTEMS
CATHODES
ELECTRON BEAMS
PLASMA EXPANSION
THERMIONIC DIODES
VELOCITY