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Title: Discrete space charge affected field emission: Flat and hemisphere emitters

Models of space-charge affected thermal-field emission from protrusions, able to incorporate the effects of both surface roughness and elongated field emitter structures in beam optics codes, are desirable but difficult. The models proposed here treat the meso-scale diode region separate from the micro-scale regions characteristic of the emission sites. The consequences of discrete emission events are given for both one-dimensional (sheets of charge) and three dimensional (rings of charge) models: in the former, results converge to steady state conditions found by theory (e.g., Rokhlenko et al. [J. Appl. Phys. 107, 014904 (2010)]) but show oscillatory structure as they do. Surface roughness or geometric features are handled using a ring of charge model, from which the image charges are found and used to modify the apex field and emitted current. The roughness model is shown to have additional constraints related to the discrete nature of electron charge. The ability of a unit cell model to treat field emitter structures and incorporate surface roughness effects inside a beam optics code is assessed.
Authors:
 [1] ; ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8]
  1. Code 6854, Naval Research Laboratory, Washington, DC 20375 (United States)
  2. Air Force Research Laboratory, Kirtland AFB, New Mexico 87117 (United States)
  3. Code 6770, Naval Research Laboratory, Washington, DC 20375 (United States)
  4. Department of Mathematics and Department of Physics, Rutgers University, Piscataway, New Jersey 08854-8019 (United States)
  5. U.S. Navy Reserve, New Orleans, Louisiana 70143 (United States)
  6. Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)
  7. Leidos, Billerica, Massachusetts 01821 (United States)
  8. Physics and Electronics Directorate, AFOSR, Arlington, Virginia 22203 (United States)
Publication Date:
OSTI Identifier:
22410225
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BEAM OPTICS; ELECTRONS; FIELD EMISSION; LIMITING VALUES; ROUGHNESS; SPACE CHARGE; STEADY-STATE CONDITIONS; SURFACES; THREE-DIMENSIONAL LATTICES