Alcator C-Mod Weekly Highlights September 22, 2008 FY2008 weeks of research operations: Target: 15 weeks Completed: 15.7 weeks Operations ---------- The installation of feltmetal on the TF arms is proceeding at the expected rate so that the lower arms will be available on time for reassembly. We have begun fabrication of upgraded instrumentation cabling for the TF voltage tap measurements following extensive Hi-Pot and liquid nitrogen cooldown tests of these new components. The fabrication of new improved insulation for the back of the arms has also begun. We are continuing a careful inspection and cleanup of the TF core fingers. We have received a recommendation from the engineers at GE, who have been inspecting our alternator, that we should not put the rotor back into service. We are considering the details of the recommendation, and examining options going forward. ICRF Systems ------------ Electrical power work on FMIT#4 is nearly complete. Both 300 A DC power supplies have been installed, DC cables have been run, and the 10 kW intermediate power amplifier (IPA) is in place. Lower Hybrid System ------------------- We continued preparation for high power testing of a copper plated 4-way splitter. Fabrication of the splitter has been completed, and it is now being installed in the test stand. Detailed thermal analysis of the full coupler systems is underway, and plans for forward and reflected power measurements are being made. Diagnostics ----------- Major challenges for fusion energy research concern materials in the boundary, where plasma and plasma facing components (PFC) couple together to form a dynamic system. To study this area, we are developing a new in-situ, 1 MeV Deuteron+, accelerator-based, PFC diagnostic, that will investigate material properties between C-Mod discharges, including surface erosion, fuel retention, and impurity densities in materials. Two three-dimensional simulations to guide the initial phases of diagnostic design have been developed. The first is an IDL-based beam dynamics simulation that models the performance of the beam inside the C-Mod vacuum vessel. The second is a particle transport-in-matter simulation, with three dimensional geometry from C-Mod solid model files, that explores particle tracking and detection within the C-Mod concrete igloo. Travel and Visits ----------------- Bruce Lipschultz and Dennis Whyte traveled to Nagasaki Japan for an ITPA meeting on SOL/divertor physics. The meeting was held over the period Sept 15 to 18, hosted by T. Tanabe and M. Sakamoto of Kyushu University. Bruce chaired the meeting and gave three talks. The first was a report on the workshop held at MIT on June 23 and 24 on assessing our knowledge of tritium retention and applying it to ITER. The other two talks were on experience with hydrogen levels in C-Mod (relevant to loads on the pumps during startup in ITER) and the level of dust in C-Mod. Dennis Whyte presented three talks at the meeting: Effect of Neutron Damage on Retention, Disruption Mitigation Requirements for ITER, and a report on the work of MIT graduate student Matt Reinke on Radiation Distribution with Massive Gas Injection. Bruce and Dennis also visited Kyushu university and saw the new QUEST ST + surface studies laboratories. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly