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Mahalingam, S.

Paper Title Page
WEPP111 Modeling Breakdown in RF Cavities Using Particle-in-cell (PIC) codes 2767
 
  • S. Mahalingam, J. R. Cary, P. Stoltz, S. A. Veitzer
    Tech-X, Boulder, Colorado
 
  A main limitation on future accelerator projects is breakdown of metallic structures. We have developed computer models of the process of breakdown using Particle-In-Cell (PIC) codes which include: Fowler-Nordheim field emission due to large surface electric fields, impact ionization of neutral gas, ion-induced secondary electron emission, ion-induced sputtering of neutrals, the effects of applied magnetic fields, plasma radiation effects, and surface heating. Two computational tools have been used to self-consistently model the breakdown. These are
  1. OOPIC Pro, a 2-Dimensional serial electromagnetic code with cylindrical coordinates, and
  2. VORPAL, a 3-Dimensional massively parallel electromagnetic code with cartesian grids.
We describe here the results of our numerical experiments including the effects of applied magnetic field strength and direction on the breakdown process, sensitivity of breakdown triggers on field emission parameters, and the potential to measure the onset of breakdown by examining impurity radiation. We show comparison with breakdown experiments performed at Fermilab and Argonne for copper structures being considered for a future muon collider project.