IPAC2015 - List of Authors (Veitzer, S.A.)

Paper	Title	Page
MOPMA037	Electron Cloud Buildup and Dissipation Models For PIP-II	626
	S.A. Veitzer, P. Stoltz Tech-X, Boulder, Colorado, 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 can cause beam degradation and limit performance in high-intensity circular particle accelerators. This is especially important in machines such as the LHC, and PIP-II, where mitigation techniques such as beam scrubbing in order to decrease the SEY are expensive and time consuming. Modeling of electron cloud buildup and dissipation can provide understanding as to the potential negative effects of electron clouds on beam properties, as well as estimates of the mitigation required to maintain accelerator performance and beam quality as accelerators move to higher intensity configurations. We report here on simulations of electron cloud buildup and dissipation for geometry, beam and magnetic field configurations describing the Recycler at Fermilab. We perform electrostatic simulations in 3D with VSim PIC, including the effects of space charge and secondary electrons. We quantify the expected survival rate of electrons in these conditions, and argue that improvements in reducing the SEY is unlikely to mitigate the electron cloud effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA037
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WEPWA059	RF Plasma-Based Ion Source Modeling on Unstructured Meshes	2637
	S.A. Veitzer, K.R.C. Beckwith, M. Kundrapu Tech-X, Boulder, Colorado, USA
	Funding: This work was performed under the auspices of the Department of Energy, Office of Basic Energy Sciences Award #DE-SC0009585. Ion source performance for accelerators and industrial applications can be improved through detailed numerical modeling and simulation. There are a number of technical complexities with developing robust models, including a natural separation of important time scales (rf, electron and ion motion), inclusion of plasma chemistry, and surface effects such as secondary electron emission and sputtering. Due to these computational requirements, it is typically difficult to simulate ion sources with Particle-In-Cell codes. An alternative is to use fluid-based codes coupled with electromagnetics in order to model ion sources. These types of models can simulate plasma evolution and rf-driven flows while maintaining good performance. We show here recent results on modeling the H⁻ ion source for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) using the fluid plasma modeling code USim. We present new meshing capabilities for generating and parallelizing unstructured computational meshes that have increased our parallel code performance and enabled us to model inductively coupled plasmas for long periods of operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Electron Cloud Buildup and Dissipation Models For PIP-II

626

S.A. Veitzer, P. Stoltz
Tech-X, Boulder, Colorado, 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 can cause beam degradation and limit performance in high-intensity circular particle accelerators. This is especially important in machines such as the LHC, and PIP-II, where mitigation techniques such as beam scrubbing in order to decrease the SEY are expensive and time consuming. Modeling of electron cloud buildup and dissipation can provide understanding as to the potential negative effects of electron clouds on beam properties, as well as estimates of the mitigation required to maintain accelerator performance and beam quality as accelerators move to higher intensity configurations. We report here on simulations of electron cloud buildup and dissipation for geometry, beam and magnetic field configurations describing the Recycler at Fermilab. We perform electrostatic simulations in 3D with VSim PIC, including the effects of space charge and secondary electrons. We quantify the expected survival rate of electrons in these conditions, and argue that improvements in reducing the SEY is unlikely to mitigate the electron cloud effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA037

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPWA059

RF Plasma-Based Ion Source Modeling on Unstructured Meshes

2637

S.A. Veitzer, K.R.C. Beckwith, M. Kundrapu
Tech-X, Boulder, Colorado, USA

Funding: This work was performed under the auspices of the Department of Energy, Office of Basic Energy Sciences Award #DE-SC0009585.
Ion source performance for accelerators and industrial applications can be improved through detailed numerical modeling and simulation. There are a number of technical complexities with developing robust models, including a natural separation of important time scales (rf, electron and ion motion), inclusion of plasma chemistry, and surface effects such as secondary electron emission and sputtering. Due to these computational requirements, it is typically difficult to simulate ion sources with Particle-In-Cell codes. An alternative is to use fluid-based codes coupled with electromagnetics in order to model ion sources. These types of models can simulate plasma evolution and rf-driven flows while maintaining good performance. We show here recent results on modeling the H⁻ ion source for the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) using the fluid plasma modeling code USim. We present new meshing capabilities for generating and parallelizing unstructured computational meshes that have increased our parallel code performance and enabled us to model inductively coupled plasmas for long periods of operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA059

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)