Alcator C-Mod Weekly Highlights September 19, 2011 FY2011 weeks of research operations Target: 15 weeks Completed: 14.5 weeks Plasma Shots: 1706 Physics ------- Dennis Whyte presented results on "Possible identification of I-mode on DIII-D" to both the C-Mod and DIII-D weekly science meetings last week. Preliminary analysis of a candidate DIII-D I-mode discharge, with ion grad-B drift pointed away from the primary X-point, appears to meet the criteria for I-mode: 1) A temperature pedestal with no/weak density pedestal 2) Modifications in the edge fluctuations and 3) Absence of typical signs of an H-mode transition in recycling. In addition, the discharge had H-mode energy confinement (H98~1) and was stationary without ELMs: common features for I-mode on C-Mod. Further experiments will be required, particularly to examine density dependence and better diagnose edge fluctuations. C-Mod's DoE postdoctoral fellow, David Pace (ORISE), has been made an official US member of the ITPA Topical Group on Energetic Particles. He joins C-Mod's Steve Wukitch as two of the seven US members. David has also been named as the Deputy Leader of the US Burning Plasma Organization Topical Group on Energetic Particles. Within the USBPO, he joins C-Mod personnel John Rice (Leader, Confinement and Transport), Jim Terry (Leader, Diagnostics), and Amanda Hubbard (Deputy Leader, Integrated Scenarios). Operations ---------- Routine maintenance of the TF and TMX power supplies continued last week in preparation for operation. The TF bypass cabinet, self-power crowbar circuits, gate drive and fault generation electronics were inspected and tested. The TMX cabinets were cleaned and inspected as were the main contactors for these supplies. ICRF Systems ------------ The vendor making modifications to the ARRA funded rotated antenna back plates made good progress last week on developing the necessary fixturing and incorporating our solid models into their CAM programming. Visits by MIT engineers to the vendor site and teleconferences have helped to ensure that information is being transferred reliably. Lower Hybrid Systems -------------------- The TPS upgrade user interface is complete. The TPS SBIR vendor is under consultation regarding details of the remote protocol implementation. Work on TPS Upgrade pinswitch/amplifier reconfiguration, testing and installation is underway. New power leads were installed on all amplifiers. Much of the remaining filament power supply documentation arrived from the vendor. Minor issues with the documentation were communicated to the vendor for clarification. G. Wallace presented recent C-Mod LH results to the RF SciDAC workshop held at the PSFC this week. The talk focused on non-inductive operation and the observed "density limit" for LHCD on C-Mod and how the RF SciDAC group can contribute to the interpretation of these experiments. Remote Participation, Travel, and Visitors ------------------------------------------ John Rice served on the thesis defense committee of Thijs Versloot at the Eindhoven Technische Universiteit, Eindhoven, the Netherlands on Sept. 12. Evan Davis, Ted Golfinopoulos and Brian LaBombard attended the BOUT++ workshop in LLNL. Evan gave a presentation entitled "BOUT++ Simulations of Edge Turbulence in the Alcator C-Mod Tokamak". Topics of discussion included modeling C-Mod's quasi-coherent mode (QCM) and the use of BOUT++ for physics interpretation and modeling of the plasma response to C-Mod's new QCM antenna system. Paul Bonoli and John Wright hosted the Annual Workshop of the SciDAC Center for Simulation of Wave-Plasma Interactions (CSWPI) at the MIT-Plasma Science and Fusion Center. The workshop was held from September 13-15, 2011 and was attended by 17 members of the CSWPI as well as by several members of the Alcator C-Mod Group, NSTX Group, Oak Ridge Technology Group, and the PSFC Theory Group. Paul Bonoli and John Wright also hosted the visit of the seminar speaker Dr. David Smithe of Tech-X Corporation who gave a talk entitled "Time Domain Simulation of a Tokamak RF Coupler". Ken Liao, U. Texas, David Pace and Aaron Bader attended the IAEA technical meeting on energetic particles in Austin, Texas from Sept 7-10. Aaron gave a 25 minutes talk titled, "ICRF minority-heated fast-ion distributions on Alcator C-Mod: Experiment and simulation" Ken gave a poster presentation titled, "Following energetic ion behavior with fast ion charge exchange during minority heating in Alcator C-Mod" David Pace presented a poster at the ITPA-EP meeting from Sept 12-13, in Austin, Texas. His title was, "Emerging Avenues for Energetic Particles Research at Alcator C-Mod" _______________________________________________ Cmod_weekly mailing list Cmod_weekly@lists.psfc.mit.edu http://lists.psfc.mit.edu/mailman/listinfo/cmod_weekly