skip to main content

Title: Emission current from a single micropoint of explosive emission cathode

Explosive emission cathodes (EECs) are widely used due to their large current. There has been much research on the explosive electron emission mechanism demonstrating that a current density of 10{sup 8}–10{sup 9 }A/cm{sup 2} is necessary for a micropoint to explode in several nanoseconds and the micropoint size is in micron-scale according to the observation of the cathode surface. This paper, however, makes an effort to research the current density and the micropoint size in another way which considers the space charge screening effect. Our model demonstrates that the relativistic effect is insignificant for the micropoint emission due to the small size of the micropoint and uncovers that the micron-scale size is an intrinsic demand for the micropoint to reach a space charge limited current density of 10{sup 8}–10{sup 9 }A/cm{sup 2}. Meanwhile, our analysis shows that as the voltage increases, the micropoint emission will turn from a field limited state to a space charge limited state, which makes the steady-state micropoint current density independent of the cathode work function and much less dependent on the electric field and the field enhancement factor than that predicted by the Fowler-Nordheim formula.
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)
  2. (China)
  3. Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)
Publication Date:
OSTI Identifier:
22493845
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 23; Journal Issue: 1; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CATHODES; CURRENT DENSITY; ELECTRIC FIELDS; ELECTRIC POTENTIAL; ELECTRON EMISSION; RELATIVISTIC RANGE; SPACE CHARGE; STEADY-STATE CONDITIONS; WORK FUNCTIONS