Breakdown

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 ? Cun1)

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-Xs physics libraries (TxPhysics)
• Improved physics and modeling capabilities
• Already links to VORPAL, but needs to be linked
  to OOPIC (OOPIC has its own models)
• Include as much physics as possible

4
Newsto 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
• Ill give a small OOPIC demo
• Fowler-Nordheim emission
• Ionization
• Fully electromagnetic RF near surface