Alcator C-Mod Weekly Highlights December 24, 2012 FY2013 weeks of research operations Target: tbd Completed: 0.53 weeks Plasma Shots: 61 Research -------- The December 20, 2012 USBPO eNews Topical Group Highlight was on "Lower Hybrid Current Dive Experiments on Alcator C-Mod", by Greg Wallace, Syun'ichi Shiraiwa, and the C-Mod LH Team. The editorial note stated that "This month's Research Highlight by G. Wallace, et al., describes experimental research using lower hybrid waves to drive plasma current in the Alcator C-Mod tokamak. In addition to experiments, this research also includes significant modeling and simulation efforts, and fusion technology development. Efficient non-inductive current drive is a demonstration goal for ITER, and it will certainly be important for electricity-producing reactors." Operations ---------- Substantial work was done on our TF magnet supply cabinets over the last few weeks aimed at reducing eddy currents in the metal cabinets and cabinet doors. Of all the mechanical work planned for this effort, only installation of a new door grounding straps remains to be completed. Advanced Outer Divertor (AOD) ----------------------------- Testing candidate springs for the advanced outer divertor continued last week. An X-750 Inconel spring was found to have little loss of overall length when compressed and heated to 600 C and may be suitable to provide connector pre-load for the inter-divertor connectors currently being designed. The design of the tiles needed to accommodate thermocouple assemblies has been completed. The design of tiles needed for the surface temperature probe assemblies is ongoing. Determination of cable wiring routes within the vessel was begun last week. A fully 3D COMSOL model of the C-Mod vessel with the new electrically continuous divertor included has been developed. The model has been run using our standard disruption specification to predict currents and loads. Toroidal eddy currents in the divertor are calculated to be ~140 kA during the disruption. Stresses due to the loads calculated in the model are within allowable limits for the divertor, a-frames and gussets, as they were for previous ANSYS models. Running the new model using the standard disruption specification while including a 400kA halo current has just begun. ICRF Systems ------------ FMIT#4 driver anode current metering issues have been resolved, and the readings are now properly calibrated with a better than 25 usec rise-time. The overload settings for both the FPA and driver have been verified and are properly set. FMIT#3 calibrations are still being determined. Bandpass filters have been located with sufficient bandwidth and low enough insertion loss to allow preparations for operation at 53 MHz to continue. Lower Hybrid Systems -------------------- The calibration of the LH antenna radial position measurement system was checked this week. The new calibration agrees with the previous calibration from April. Calibration data were taken for the double-stub FFT across the range of ± 2 A in the coil supplies. This data will be used to generate a lookup table for the coil currents used in the matching circuit. Weight estimates of the 4th cart equipment racks were generated for structural analysis of the proposed LH mezzanine extension. Two locations for the mezzanine extension are under consideration: in the NW corner of the cell near the location of the 4th cart, and along the E wall of the cell near the 1st cart. A 3-D CAD model of the mezzanine has been created to aid in this process. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly