1. Breakdown – Phase I K. Paul, S. Veitzer, P. Stoltz, D. Smithe (Tech-X) J. Norem (Argonne National Lab) “The objective of this work is to improve modeling of breakdown in devices relevant to muon cooling by adding to PIC codes processes like plasma radiation and multiple ionization.” (i.e., We want to improve our PIC codes such that they can thoroughly study breakdown in RF cavities. We want to make our codes as “capable” as possible.) Tech-X Corporation http://www.txcorp.com August 22, 2007

2. Objectives Determine the best way to model radiation effects in metallic breakdown processes Radiation is emitted from metallic plasma (line and continuum radiation) that carries energy out of the system e.g., Coronal model (compute fluid quantities on grid from particles, remove energy from fluid, and back…) Determine the best way to model high charge state ions in metallic breakdown processes Multiple ionization for metallic gases e.g., Lotz model (Cun→ Cun+1)

3. Techniques • Use 2 different Tech-X PIC codes: • OOPIC Pro: Easy to use; Great for small scale problems and exploratory runs • VORPAL: More complex; Massively parallel (1000+ node clusters); “Next Stage” simulation tool • Add to Tech-X’s physics libraries (TxPhysics) • Improved physics and modeling capabilities • Already links to VORPAL, but needs to be linked to OOPIC (OOPIC has it’s own models) • Include “as much physics as possible”

4. News…to come • Peter Stoltz and Seth Veitzer can come early next year to present results/work on this Phase I • Direct all questions to them  • New ideas can definitely go into a Phase II proposal • I’ll give a small OOPIC demo • Fowler-Nordheim emission • Ionization • Fully electromagnetic RF near surface