• H. Okamoto, H. Sugimoto
  HU/AdSM, Higashi-Hiroshima
• M. Ikegami
  JAEA/Kansai, Kyoto
• J. Wei
  TUB, Beijing
• Y. Yuri
  JAEA/TARRI, Gunma-ken

An ultimate goal in accelerator physics is to produce a "zero-emittance" beam, which is equivalent to making the beam temperature the absolute zero in the center-of-mass frame. At this limit, if somehow reached, the beam is Coulomb crystallized. Schiffer and co-workers first applied the molecular dynamics (MD) technique to study the fundamental features of various Coulomb crystals. Their pioneering work was later generalized by Wei et al. who explicitly incorporated discrete alternating-gradient lattice structures into MD simulations. This talk summarizes recent numerical efforts made to clarify the dynamic behavior of ultra-cold and crystalline ion beams. The MD modeling of beam crystallization in a storage ring is outlined, including how one can approach the ultra-low emittance limit. Several possible methods are described of cooling an ion beam three-dimensionally with radiation pressure (the Doppler laser cooling).

Slides

• A. Friedman, J.J. Barnard, R.H. Cohen, D.P. Grote, S.M. Lund, W. M. Sharp
  LLNL, Livermore, California
• R.C. Davidson, M. Dorf, I. Kaganovich
  PPPL, Princeton, New Jersey
• A. Faltens, E. Henestroza, J.-Y. Jung, J.W. Kwan, E. P. Lee, M. Leitner, J.-L. Vay, W.L. Waldron
  LBNL, Berkeley, California

The near-term mission of the Heavy Ion Fusion Science Virtual National Laboratory (a collaboration of LBNL, LLNL, and PPPL) is to study "warm dense matter" at ~1 eV heated by ion beams; a longer-term topic is ion-driven target physics for inertial fusion energy. Beam bunch compression factors exceeding 50x have been achieved on the Neutralized Drift Compression Experiment (NDCX) at LBNL, enabling rapid target heating; however, to meet our goals an improved platform, NDCX-II, is required. Using refurbished induction cells from the decommissioned Advanced Test Accelerator at LLNL, NDCX-II will compress a ~500 ns pulse of Li+ ions to ~1 ns while accelerating it to 3-4 MeV (a spatial compression of 100-150x) over ~15 m. Non-relativistic ions exhibit complex dynamics; the beam manipulations in NDCX-II are actually enabled by strong longitudinal space charge forces. We are using analysis, an interactive 1D PIC code (ASP) with optimizing capabilities and a centroid-offset model, and both (r,z) and 3D Warp-code simulations, to develop the NDCX-II accelerator. Both Warp and LSP are used for plasma neutralization studies. This talk describes the methods used and the resulting physics design.