| Synthesizing
a 4D Beam Particle Distribution from Multiple 2D Views
Discrete-particle simulations are commonly employed to understand
the behavior of particle beams in heavy ion fusion. Integrated
simulations, beginning at the source and carried out in full
time-dependent 3D, or a reduced description when appropriate,
offer the promise of the greatest fidelity in describing the
long-term beam behavior. However, the source, injector, and
beamline upstream of a section of interest in an experiment
are usually not completely characterized. Thus, the beam distribution
function in a simulation beginning at the source generally
drifts away from the experimentally measured beam distribution,
and it can be challenging to adjust the beamline description
and other parameters in the simulation to bring them back
into agreement.
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| Figure
5 WARP-3D simulation of the electrostatic
quadrupole injector at the front end of the High Current
Experiment (HCX); the simulated beam at the exit plane
was used as a test problem for the new 4D synthesis algorithms. |
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As a complement to integrated simulations and as a tool for
routine experimental analysis, Friedman et al. are developing
the ability to launch particle simulations of “real”
experiments, using an initial beam particle distribution derived
from experimental measurements at a station partway along
the machine (Figure 5). Specifically, they have begun developing
algorithms to synthesize the 4D phase space distribution of
the beams from the reduced 2D experimental data. Their initial
simulations verify the importance of such a synthetic procedure,
since simulations launched using simpler model distributions
with low-order moments matching those of the observed beam
fail to reproduce the correct dynamics.
INVESTIGATORS
A. Friedman and D. P. Grote, Lawrence Livermore National Laboratory;
C. M. Celata and J. W. Staples, Lawrence Berkeley National
Laboratory.
PUBLICATION
A. Friedman, D. P. Grote, C. M. Celata, and J. W. Staples,
“Synthesizing a four-dimensional beam particle distribution
from multiple two-dimensional views,” Phys. Rev. ST
Accel. Beams (submitted); Lawrence Berkeley National Laboratory
report LBNL-49647.
URL
http://hif.lbl.gov/
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