Burkhard JUETTNER
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The book is devoted to the theoretical and computational research of the physical processes in cathodic region of the electric arc in a vapour of the cathode material. The self-sustained physical and mathematical models were developed for the processes occurring on the cathode surface, in the near-cathode plasma and the cathode bulk. The calculated values agree fairly well with experimental results in the cases where the latter are available. The influence on the Thermo-Field (F-T) electron emission of the electrical field of individual ions (I-F-T mechanism), incoming to the surface from the plasma, is investigated in detail. Parameters of the near-cathode plasma and the computing simulation results for the dynamics, structure and parameters of the cathode spot are presented. Together with the plasma parameters, 1D and 2D modeling of heat conduction at the cathode surface yields information on the time scale of the spot processes and the spot size. Thus, the gap between theory and experiment is narrowed. The spot appears to be a nanosecond phenomenon with a high density of power and current. By virtue of an uninterrupted sequence of reignitions the cathode works in a quasi-stationary regime, being able to deliver virtually unlimited discharge currents for all conducting materials.
Chapter 2. Electron Emission Chapter 3. The Near Cathode Plasma Chapter 4. Heat Conduction at the Cathode Surface Chapter 5. Summary of the Theoretic Results Chapter 6. Experiments References WELDING AND ALLIED PROCESSES
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