Two-Dimensional Short-Pulse Child-Langmuir Law

Summary form only given. Advances in laser-driven electron photo-injectors have pushed the operation of the photocathode from the normally source-limited regime to the space-charge limited regime. As the pulse length of the photo-injector is usually shorter than the transit time of the electrons acr...

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Bibliographic Details
Main Authors: Koh, W.S., Ang, L.K.
Format: Conference Proceeding
Language:English
Subjects:
Cathodes
Charge measurement
Current measurement
Electrons
Optical pulses
Plasma density
Plasma measurements
Plasma temperature
Surface emitting lasers
Temperature measurement
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Summary:Summary form only given. Advances in laser-driven electron photo-injectors have pushed the operation of the photocathode from the normally source-limited regime to the space-charge limited regime. As the pulse length of the photo-injector is usually shorter than the transit time of the electrons across the vacuum gap, the classical Child-Langmuir (CL) law is expected to be exceeded as shown in previous experiments. Agust et al. has extended the classical 1D CL law to include the influence of a finite pulse length. However, in practical situations, the area and shape of the photocathode emitter are also important parameters to be considered. In this paper, we will present a simple theory of 2D or 3D short-pulse CL law for various emitting patches such as an infinitely long strip of width W, and a circular emitting patch of radius R. Our results are then compared with 2D or 3D PIC simulation, which show good agreements. Multi-pulse effects will also be discussed
ISSN:0730-9244
2576-7208
DOI:10.1109/PLASMA.2005.359411