Kiel 2011 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 20: Simulationsverfahren / Theorie/Modellierung II
P 20.4: Vortrag
Donnerstag, 31. März 2011, 11:45–12:00, HS H
Monte Carlo Simulation of the Breakdown in Copper Vapor at Low Pressure — Dirk Uhrlandt1, Detlef Loffhagen1, and •Kai Hencken2 — 1Leibniz Institute for Plasma Science and Technology e.V. (INP), Felix-Hausdorff-Str. 2, D-17489 Greifswald — 2ABB Switzerland Ltd, Corporate Research, Segelhof 1, CH-5405 Dättwil, Switzerland
The breakdown conditions of copper vapor at low pressure are studied in a Monte Carlo simulation of electrons, copper ions and atoms. This is of interest for the dielectric breakdown strength of a vacuum interrupter after current zero, where hot vapor is still evaporated from the electrodes. In a one dimensional simulation the movement and the multiplication of electrons, ions and fast atoms in inelastic collisions and ionization processes are followed taking into account the atomic cross sections to excited atomic states, as well as, the ionization cross section to single and double charged ions. The secondary electron emission due to the heavy particles is calculated by following them until they reach the cathode and taking into account energy and charge state. By scanning a large range of gas densities and electric voltages, the boundary of the breakdown region has been determined. A lower limit for the critical voltage is found corresponding to the usual Paschen curve. In addition an upper limit was found, which is due to the increase of run-away electrons, which at high energies cross the whole gap without collisions with the atoms. In addition the simulation allows studying detailed energy distributions of both electrons and ions across the gap.