2011 Particle Accelerator Conference - List of Authors (Bazouin, G.)

Paper

Title

Page

Time-Dependent Phase-Space Measurements of the Longitudinally Compressing Beam in NDCX-I

61

S.M. Lidia, G. Bazouin, P.A. Seidl
LBNL, Berkeley, California, USA

Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore Warm Dense Matter physics. A ~150 kV, ~500 ns ramped voltage pulse is applied to a ~300 keV, 5-10 μs, 25 mA K+ ion beam across a single induction gap. The velocity modulated beam compresses longitudinally during ballistic transport along a space-charge-neutralizing plasma transport line, resulting in ~3A peak current with ~2-3 ns pulse durations (FWHM) at the target plane. Transverse final focusing is accomplished with a ~8 T, 10 cm long pulsed solenoid magnet. Time-dependent focusing in the induction gap, and chromatic aberrations in the final focus optics limit the peak fluence at the target plane for the compressed beam pulse. We report on time-dependent phase space measurements of the compressed pulse in the ballistic transport beamline, and measurement of the time-dependent radial impulses derived from the interaction of the beam and the induction gap voltage. We present results of start-to-end simulations to benchmark the experiments. Fast correction strategies are discussed with application to both NDCX-I and to the new NDCX-II accelerator.

Slides MOOCS4 [7.432 MB]

WEP099

Numerical Solution for the Potential and Density Profile of a Thermal Equilibrium Sheet Beam

1659

S.M. Lund
LLNL, Livermore, California, USA
G. Bazouin
LBNL, Berkeley, California, USA

Funding: This research was performed under the auspices of the US DOE at the Lawrence Livermore and Lawrence Berkeley National Laboratories under contract numbers DE-AC52-07NA27344 and DE-AC02-05CH11231.
A one-dimensional Vlasov-Poisson model for sheet beams is presented to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet beam model is applied to analyze several problems of fundamental interest. First, a sheet beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- and three-dimensional thermal equilibrium models in terms of the equilibrium structure and Deybe screening properties. Second, the simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad which suggesting robust stability properties for beams with strong space-charge.

Paper	Title	Page
MOOCS4	Time-Dependent Phase-Space Measurements of the Longitudinally Compressing Beam in NDCX-I	61
	S.M. Lidia, G. Bazouin, P.A. Seidl LBNL, Berkeley, California, USA
	Funding: This work was supported by the Director, Office of Science, Office of Fusion Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. The Neutralized Drift Compression Experiment (NDCX-I) generates high intensity ion beams to explore Warm Dense Matter physics. A ~150 kV, ~500 ns ramped voltage pulse is applied to a ~300 keV, 5-10 μs, 25 mA K+ ion beam across a single induction gap. The velocity modulated beam compresses longitudinally during ballistic transport along a space-charge-neutralizing plasma transport line, resulting in ~3A peak current with ~2-3 ns pulse durations (FWHM) at the target plane. Transverse final focusing is accomplished with a ~8 T, 10 cm long pulsed solenoid magnet. Time-dependent focusing in the induction gap, and chromatic aberrations in the final focus optics limit the peak fluence at the target plane for the compressed beam pulse. We report on time-dependent phase space measurements of the compressed pulse in the ballistic transport beamline, and measurement of the time-dependent radial impulses derived from the interaction of the beam and the induction gap voltage. We present results of start-to-end simulations to benchmark the experiments. Fast correction strategies are discussed with application to both NDCX-I and to the new NDCX-II accelerator.
	Slides MOOCS4 [7.432 MB]

WEP099	Numerical Solution for the Potential and Density Profile of a Thermal Equilibrium Sheet Beam	1659
	S.M. Lund LLNL, Livermore, California, USA G. Bazouin LBNL, Berkeley, California, USA
	Funding: This research was performed under the auspices of the US DOE at the Lawrence Livermore and Lawrence Berkeley National Laboratories under contract numbers DE-AC52-07NA27344 and DE-AC02-05CH11231. A one-dimensional Vlasov-Poisson model for sheet beams is presented to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet beam model is applied to analyze several problems of fundamental interest. First, a sheet beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- and three-dimensional thermal equilibrium models in terms of the equilibrium structure and Deybe screening properties. Second, the simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad which suggesting robust stability properties for beams with strong space-charge.