IPAC2013 - List of Authors (Bruhwiler, D.L.)

Paper

Title

Page

Coherent Electron Cooling: Status of Single-Pass Simulations

1049

B.T. Schwartz, G.I. Bell, I.V. Pogorelov, S.D. Webb
Tech-X, Boulder, Colorado, USA
D.L. Bruhwiler
CIPS, Boulder, Colorado, USA
Y. Hao, V. Litvinenko, G. Wang
BNL, Upton, Long Island, New York, USA
S. Reiche
PSI, Villigen PSI, Switzerland

Funding: US DOE Office of Science. Contracts DE-FC02-07ER41499, DE-FG02-08ER85182, DE-AC02-05CH11231.
Advances in nuclear physics depend on experiments that employ relativistic hadron accelerators with dramatically increased luminosity. Current methods of increasing hadron beam luminosity include stochastic cooling and electron cooling; however, these approaches face serious difficulties at the high intensities and high energies proposed for eRHIC *. Coherent electron cooling promises to cool hadron beams at a much faster rate**. A single pass of an ion through a coherent electron cooler involves the ion's modulating the charge density of a copropagating electron beam, amplification of the modulated electron beam in a free-electron laser, and energy correction of the ion in the kicker section. Numerical simulations of these three components are underway, using the parallel Vorpal framework and Genesis 1.3, with careful coupling between the two codes. Here we present validations of two components of the simulations: Adding bunching to an electron beam at the start of an FEL, and the time-dependent charge density modulation in the kicker.
* http://www.bnl.gov/cad/eRHIC/
** V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).

TUPWO059

Reducing Emittance of a H⁻ Beam in a Solenoid-based Low-energy Beam Transport through Numerical Modeling

2000

J. von Stecher, D.L. Bruhwiler, B.T. Schwartz, S.A. Veitzer
Tech-X, Boulder, Colorado, USA
B. Han, M.P. Stockli
ORNL, Oak Ridge, Tennessee, USA

Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844
A solenoid-based low-energy beam transport (LEBT) subsystem is under development for the H⁻ linac front end of the Spallation Neutron Source. The LEBT design includes MHz frequency chopping of the partially neutralized H⁻ beam that can potentially lead to beam instabilities. We report results of numerical modeling using the parallel Vorpal framework for 3D electrostatic particle-in-cell (PIC) to simulate H⁻ beam dynamics in the LEBT, over multiple chopping events. We detail how the addition of a positively biased potential barrier near the entrance of the chopper can improve LEBT performance by eliminating chopper-induced emittance increases over many chopping events.
DLB is now at University of Colorado, Boulder

THYB101

Suppressing Transverse Beam Halo with Nonlinear Magnetic Fields

3099

S.D. Webb, D.T. Abell, D.L. Bruhwiler, J.R. Cary
Tech-X, Boulder, Colorado, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
S. Nagaitsev, A. Valishev
Fermilab, Batavia, USA

Funding: This work was supported in part by the US Department of Energy's Office of Science, Office of High Energy Physics, under grant No. DE-SC0006247.
Traditional space charge driven resonances, such as beam halo, arise due to the underlying linear nature of accelerator lattices. In this talk, we present initial results on a new class of intrinsically nonlinear lattices, which introduce a large tune spread naturally. The resulting nonlinear decoherence suppresses the onset of beam halo.

Slides THYB101 [63.510 MB]

Paper	Title	Page
MOPWO071	Coherent Electron Cooling: Status of Single-Pass Simulations	1049
	B.T. Schwartz, G.I. Bell, I.V. Pogorelov, S.D. Webb Tech-X, Boulder, Colorado, USA D.L. Bruhwiler CIPS, Boulder, Colorado, USA Y. Hao, V. Litvinenko, G. Wang BNL, Upton, Long Island, New York, USA S. Reiche PSI, Villigen PSI, Switzerland
	Funding: US DOE Office of Science. Contracts DE-FC02-07ER41499, DE-FG02-08ER85182, DE-AC02-05CH11231. Advances in nuclear physics depend on experiments that employ relativistic hadron accelerators with dramatically increased luminosity. Current methods of increasing hadron beam luminosity include stochastic cooling and electron cooling; however, these approaches face serious difficulties at the high intensities and high energies proposed for eRHIC . Coherent electron cooling promises to cool hadron beams at a much faster rate. A single pass of an ion through a coherent electron cooler involves the ion's modulating the charge density of a copropagating electron beam, amplification of the modulated electron beam in a free-electron laser, and energy correction of the ion in the kicker section. Numerical simulations of these three components are underway, using the parallel Vorpal framework and Genesis 1.3, with careful coupling between the two codes. Here we present validations of two components of the simulations: Adding bunching to an electron beam at the start of an FEL, and the time-dependent charge density modulation in the kicker. http://www.bnl.gov/cad/eRHIC/ ** V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).

TUPWO059	Reducing Emittance of a H⁻ Beam in a Solenoid-based Low-energy Beam Transport through Numerical Modeling	2000
	J. von Stecher, D.L. Bruhwiler, B.T. Schwartz, S.A. Veitzer Tech-X, Boulder, Colorado, USA B. Han, M.P. Stockli ORNL, Oak Ridge, Tennessee, USA
	Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844 A solenoid-based low-energy beam transport (LEBT) subsystem is under development for the H⁻ linac front end of the Spallation Neutron Source. The LEBT design includes MHz frequency chopping of the partially neutralized H⁻ beam that can potentially lead to beam instabilities. We report results of numerical modeling using the parallel Vorpal framework for 3D electrostatic particle-in-cell (PIC) to simulate H⁻ beam dynamics in the LEBT, over multiple chopping events. We detail how the addition of a positively biased potential barrier near the entrance of the chopper can improve LEBT performance by eliminating chopper-induced emittance increases over many chopping events. DLB is now at University of Colorado, Boulder

THYB101	Suppressing Transverse Beam Halo with Nonlinear Magnetic Fields	3099
	S.D. Webb, D.T. Abell, D.L. Bruhwiler, J.R. Cary Tech-X, Boulder, Colorado, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA S. Nagaitsev, A. Valishev Fermilab, Batavia, USA
	Funding: This work was supported in part by the US Department of Energy's Office of Science, Office of High Energy Physics, under grant No. DE-SC0006247. Traditional space charge driven resonances, such as beam halo, arise due to the underlying linear nature of accelerator lattices. In this talk, we present initial results on a new class of intrinsically nonlinear lattices, which introduce a large tune spread naturally. The resulting nonlinear decoherence suppresses the onset of beam halo.
	Slides THYB101 [63.510 MB]