PAC2013 - List of Authors (Lebrun, P.)

Paper	Title	Page
MOPBA24	Integrated Kinetic and Plasma Dielectric Models of Electron Cloud Buildup and TE Wave Transmission	228
	S.A. Veitzer, P. Stoltz Tech-X, Boulder, Colorado, USA P. Lebrun Fermilab, Batavia, USA
	Funding: This work was performed under the auspices of the Department of Energy as part of the ComPASS SCiDAC-2 project (DE-FC02-07ER41499), and the SCiDAC-3 project (DE-SC0008920) Buildup of electron plasmas in accelerator cavities poses a serious threat to performance for current and future accelerators. Traveling-wave rf diagnostics are an effective, non-destructive way to measure electron clouds, although determining the true cloud density from spectra is difficult due to the effects of reflections, nonuniform cloud density, and magnetic field effects. We model one beam revolution period of plasma buildup electrostatically, with a kinetic PIC model, using a longer time step; thus determining the cloud density. Then we perform electromagnetic simulations with a finer time resolution, using this density as a plasma dielectric tensor, over many revolution periods in order to simulate rf spectra and sidebands that arise because of the modulation of the plasma. Using a plasma dielectric model increases the numerical stability and speed of the models, allowing for very long time scale simulations needed to reproduce spectra as observed in real experiments. We compare here the differences in computed side band spectra due to different magentic field configurations for Main Injector parameters.

Paper

Title

Page

Integrated Kinetic and Plasma Dielectric Models of Electron Cloud Buildup and TE Wave Transmission

228

S.A. Veitzer, P. Stoltz
Tech-X, Boulder, Colorado, USA
P. Lebrun
Fermilab, Batavia, USA

Funding: This work was performed under the auspices of the Department of Energy as part of the ComPASS SCiDAC-2 project (DE-FC02-07ER41499), and the SCiDAC-3 project (DE-SC0008920)
Buildup of electron plasmas in accelerator cavities poses a serious threat to performance for current and future accelerators. Traveling-wave rf diagnostics are an effective, non-destructive way to measure electron clouds, although determining the true cloud density from spectra is difficult due to the effects of reflections, nonuniform cloud density, and magnetic field effects. We model one beam revolution period of plasma buildup electrostatically, with a kinetic PIC model, using a longer time step; thus determining the cloud density. Then we perform electromagnetic simulations with a finer time resolution, using this density as a plasma dielectric tensor, over many revolution periods in order to simulate rf spectra and sidebands that arise because of the modulation of the plasma. Using a plasma dielectric model increases the numerical stability and speed of the models, allowing for very long time scale simulations needed to reproduce spectra as observed in real experiments. We compare here the differences in computed side band spectra due to different magentic field configurations for Main Injector parameters.