Intense Electron Emission from Laser Produced Plasmas

  • G. Siller
  • K. Büchl
  • H. Hora


Measurements are reported in which laser pulses are used to produce plasmas at tantalum targets biased as cathode against an anode by a voltage UA = 30 to 200 kV. The electron emission currents during 100 nsec are a few hundred amperes up to 1 kA. The brightness of the emitted electron beams is more than a hundred times better than in beams generated from comparable field emission sources. The energy spread at 100 kV anode voltage is less than 800 eV. The measured high electron currents cannot be explained by classical thermionic emission because space charge effects permit currents a factor of 10-4 less than observed. We suggest that self-focusing filaments are created by the laser at the ends of which the nonlinear force preaccelerates the electron in the space-charge free surface region of the plasma up to some keV energy. With such initial velocities the electrons in vacuum are not restricted by space-charge effects. Thus model also explains the independence of the emission current J of the focusing, the linear continuation of the measured dependence of J on UA and the slope of J on the laser power P by a P3/4 law.


Laser Power Space Charge Electron Emission Emission Current Space Charge Effect 


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Copyright information

© Springer Science+Business Media New York 1972

Authors and Affiliations

  • G. Siller
    • 1
  • K. Büchl
    • 1
  • H. Hora
    • 1
    • 2
  1. 1.Max-Planck-Institut für PlasmaphysikEuratom AssociationGarchingGermany
  2. 2.Rensselaer Polytechnic InstituteUSA

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