HU/AdSM, Higashi-Hiroshima
JAEA/Kansai, Kyoto
TUB, Beijing
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).
KEK, Ibaraki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
BNL, Upton, Long Island, New York
The beam commissioning of J-PARC linac has been performed since November 2006, and we are now in a transitional phase from an initial commissioning stage to a stage where we seek more stable operation with higher beam power. In the beam commissioning, the modeling is important to understand the underlying physics of the experimental data obtained by beam monitors. As the J-PARC is a high-intensity proton accelerator facility, the beam is subject to strong space-charge effects. In addition, mitigation of the beam loss is critically important to avoid excess radio-activation of the accelerator components. Therefore, an accurate Particle-In-Cell simulation code plays an essential role in the beam commissioning, especially in mapping out our course in the beam commissioning planning. For this purpose, we have been using IMPACT code in J-PARC linac. In this paper, we review the simulation studies performed for J-PARC linac trying to understand the experimental results in the course of the beam commissioning efforts.