Electron beam current in high power cylindrical diode

Journal Article · Fri Jan 15 04:00:00 EST 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3292655· OSTI ID:21344671

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

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

Intense electron beam generation studies were carried out in high power cylindrical diode to investigate the effect of the accelerating gap and diode voltage on the electron beam current. The diode voltage has been varied from 130 to 356 kV, whereas the current density has been varied from 87 to 391 A/cm{sup 2} with 100 ns pulse duration. The experimentally obtained electron beam current in the cylindrical diode has been compared with the Langmuir-Blodgett law. It was found that the diode current can be explained by a model of anode and cathode plasma expanding toward each other. However, the diode voltage and current do not follow the bipolar space-charge limited flow model. It was also found that initially only a part of the cathode take part in the emission process. The plasma expands at 4.2 cm/mus for 1.7 cm anode-cathode gap and the plasma velocity decreases for smaller gaps. The electrode plasma expansion velocity of the cylindrical diode is much smaller as compared with the planar diode for the same accelerating gap and diode voltage. Therefore, much higher voltage can be obtained for the cylindrical diodes as compared with the planar diodes for the same accelerating gap.

• OSTI ID: 21344671
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 1 Vol. 17; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANODES
BEAMS
CATHODES
CURRENT DENSITY
CURRENTS
DIODE TUBES
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ELECTRODES
ELECTRON BEAMS
ELECTRON TUBES
EXPANSION
LEPTON BEAMS
PARTICLE BEAMS
PLASMA EXPANSION
SPACE CHARGE
THERMIONIC DIODES
THERMIONIC TUBES
VELOCITY