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Field electron emissions: influence of a magnetic field and relativistics ef-fects


Presented Institute of Applied Physics of National Academy of Sciences of Ukraine.

Lebedynskyi S. O., Researcher, Department of Quantum Electrodynamics of Strong Fields №40, Institute of Applied Physics, NAS of Ukraine;

The aim of the study is the construction of a theory of the field electron emission from metals with an external magnetic field. The study received the following scientific results:

  • the assumption that the transmission coefficient of the potential barrier is independent of the magnetic field parallel to the electric field, which was used to construct the theory of field emission in this configuration of fields was proved;
  • a relativistic generalization of the Fowler-Nordheim theory describing the phenomenon of field emission from a metal was made, and an expression for the transmission coefficient of a potential barrier was generalized to the relativistic case;
  • the Lorentz contraction of a potential barrier at the metal-vacuum interface, which leads to an increasing in the transmission coefficient has been found;
  •   a generalization of the Fowler-Nordheim equation, enabling us to consider the effect of an external magnetic field parallel to the metal surface on the transmission coefficient was made. An expression for the transmission coefficient was found when the condition  is satisfied;
  •  an analytical expression for the coefficient of transmission of the potential barrier, which is valid for the values of the electric field strength and the work function of the electron from the metal, both for laboratory parameters of the field emission and for the field emission from pulsars, was obtained;
  • the decrease in breakdown voltage, which was observed in the experiments of IAP NASU and CERN, as a result of the increase in the dark current through the elongation of the trajectories of electrons formed in the electrode gap in the presence of a magnetic field parallel to the surface was explained.

In these works explains the experimentally obtained decrease in resistance to breakdowns in the presence of an external magnetic field parallel to the electrodes in the experiments made at the IAP NASU and CERN and gives recommendations for preventing breakdown by applying a magnetic field larger then cutt-off magnetic field. The obtained results can be used in research centers around the world in further experiments to increase the stability of accelerating structures to vacuum breakdowns.

Number of publications: 15 works including 6 articles in reviewed journals and 9 reports in proceedings of scientific conferences.