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Grisham, L.

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MOOBC02 Experiments in Warm Dense Matter using an Ion Beam Driver 140
 
  • F. M. Bieniosek, M. Leitner, B. G. Logan, R. More, P. N. Ni, P. K. Roy
    LBNL, Berkeley, California
  • J. J. Barnard, M. Kireeff Covo, A. W. Molvik
    LLNL, Livermore, California
  • L. Grisham
    PPPL, Princeton, New Jersey
  • H. Yoneda
    University of electro-communications, Tokyo
 
  Funding: Work performed under the auspices of the U. S. Dept. of Energy by LBNL, LLNL, and PPPL under Contracts No. W-7405-Eng-48, DE-AC02-05CH11231, and DE-AC02-76CH3073.

We describe near term heavy-ion beam-driven warm dense matter (WDM) experiments. Initial experiments are at low beam velocity, below the Bragg peak, increasing toward the Bragg peak in subsequent versions of the accelerator. The WDM conditions are envisioned to be achieved by combined longitudinal and transverse neutralized drift compression to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. Initial candidate experiments include an experiment to study transient darkening in the WDM regime; and a thin target dE/dx experiment to study beam energy and charge state distribution in a heated target. Further experiments will explore target temperature and other properties such as electrical conductivity to investigate phase transitions and the critical point.

 
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THPAS082 Meter-Long Plasma Source for Heavy Ion Beam Space Charge Neutralization 3672
 
  • P. Efthimion, R. C. Davidson, E. P. Gilson, L. Grisham
    PPPL, Princeton, New Jersey
  • B. G. Logan, P. A. Seidl, W. L. Waldron, S. Yu
    LBNL, Berkeley, California
 
  Funding: Research supported by the U. S. Department of Energy.

Plasmas are sources of electrons for charge neutralizing ion beams to allow them to focus to small spot sizes and compress their axial pulse length. Sources must operate at low pressures and without strong electric/magnetic fields. To produce meter-long plasmas, sources based on ferroelectric ceramics with large dielectric coefficients were developed. The sources use BaTiO3 ceramic to form plasma. The drift tube inner wall of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic and ~7 kV is applied across the wall of the ceramics. A 20-cm-long prototype source produced plasma densities of 5·1011 cm-3. It was integrated into the Neutralized Transport Experiment and successfully neutralized the K+ beam. A one-meter-long source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma over the length of the source in the 1·1010 cm-3 range. This source was integrated into NDCX for beam compression experiments. Experiments with this source yielded compression ratios ~80. Future work will consider longer and higher plasma density sources to support beam compression and high energy density experiments.