Alcator C-Mod Weekly Highlights January 5, 2009 FY2009 weeks of research operations: Target: TBD Completed: 0 weeks Physics ------- Dennis Whyte, in collaborative work with the FOM-Netherlands plasma group, is studying supersonic plasma exhaust in collisional plasmas. Supersonic plasma speeds were observed in the Pilot-PSI linear plasma device when negative biasing was applied to the target. Two-point models for momentum and energy have been developed which suggest that the imposition of large ohmic heating in a highly collisional plasma forced a large fraction of the imposed external bias across the bulk of the plasma rather than the sheath. Similar conditions are often found at the detached inner divertor of C-Mod, where large parallel currents are set by the large T gradient in the SOL to the attached outer divertor. Operations ---------- The OH1 and OH2L coaxes have been checked for proper contact pressure, installed, successfully high-potted, and undergone an AC ring test. The AC test verifies that the electrical circuit formed by the magnet and the coax is performing as expected. All OH and EF coax and magnet systems have now been successfully tested. The TF core plate-to-plate resistances have been re-checked with very good results following the move to the assembly stand. Our vendors performing the alternator inspection will return on Tuesday to resume work. We expect the ultrasonic inspection of the second half of the rotor to be complete by early next week. A representative from the vendor selected to take the ring sample from the rotor core visited MIT to discuss details of this process. Tooling is being developed that will be tested on a model of the rotor core at their facility. Lower Hybrid System ------------------- Testing of the new Coupler Protection System boards continued last week. The client side API (Application Programming Interface) for reading and writing data to the PIC32 processor is complete and tested. An MDSip client for writing data from the system directly into MDSplus is also being developed, with a fall-back to an already developed ASCII string interface if needed. ICRF Systems ------------ Testing of the FPA (Final Power Amplifier) grid regulator continued last week. Diagnostics ----------- A meeting on changes to the K-Hor flange to allow for new diagnostics and upgrades to old ones will be held this Wednesday. A review of the MSE (Motional Stark Effect) thermal shield design will also be held this week. _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly