Heavy ion drivers for a fusion ignition facility require production and transport of very intense ion beams. Recent observations and studies on high-intensity beams clearly show that electron accumulation inside the beam pipe and related effects like degradation of the vacuum and induced beam insbilities can be the actual limitation in the performance of new and existing machines, and therefore should have significant impact on the design of high-intensity/high-power acceelerators. The necessity to cope with electron cloud issues requires an expansion of methods, which we plan to achieve by joining the competence of the applicant in accelerator physics and electron cloud matters in particular, the opportunity to use GSI facilities to carry out measurements and the expertise of the host group (High-Current Beam Physics) in advanced techniques of computing and plasma physics.
We intend to address the following items: development of analytical tools to describe two-stream effects associated with the electron cloud, development of 3D simulation programs with all ingredients needed for realistic modelling of the build up process and the interaction beam-cloud, optimisation of the codes achievable through parallelisation and benchmarking, machine and laboratory measurements to validate theory and simulations. All the above listed points are estimated to require a two years time to be carried out.
The training content of our research project is rich and various. The applicant would have a chance to apply and broaden his knowledge of electron cloud issues and general accelerator physics by inter-action the GSI environment presently in evolution, acquire experience in parallel computing and control room operation, become familiar with applications of high-intensity beams for plasma physics and Inertial Fusion Energy. The use of the existing GSI facilities is also a unique tool to investigate the impact of electron cloud on heavy ion drivers experimentally. The expected impact for GSI would be to gain a deeper insight, understanding and control of electron cloud and related ion loss mechanisms (e.g., instabilities, gas desorption) for the existing machines and for upgrade to the new project with yet larger intensities, use of 20-30 kJ bunches of U^28+ for plasmaphysics experiments, and extrapolation to the problem in a full fusion driver.