LLNL, Livermore, California
PPPL, Princeton, New Jersey
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.
GSI, Darmstadt
ITEP, Moscow
IAP, Frankfurt am Main
During the last year several numerical investigations have been started at GSI in order to improve the performance of the linear accelerator facility. The main activities regard the upgrade of the high current UNILAC accelerator including the severe upgrade of the HSI injector, the HITRAP decelerator and, in the frame of the future FAIR project, the development of the new dedicated proton linac. End to end beam dynamics simulations are a powerful tool concerning the machine design, commissioning and optimization. Particle distributions, generated from beam emittance measurements, are transferred through the whole chain of the accelerating structures and beam transport lines. Detailed calculations of the space charge effects as well as external and measured mapping of the structures electromagnetic fields are used to provide the most reliable results. The paper presents a general overview of all activities including a comparison with experimental results.
IAP, Frankfurt am Main
For the development of high energy and high duty cycle RFQs accurate particle dynamic simulation tools are important for optimizing designs, especially in high current applications. To describe the external fields in RFQs, the Poisson equation has to be solved taking the boundary conditions into account. In PteqHI this is now done by using a finite difference method on a grid. This method will be described and simulation results will be compared to different RFQ particle dynamic codes.