Initial Operation of The TCS Upgrade
Author: Kenneth E Miller
Requested Type: Poster Only
Submitted: 2006-12-18 18:56:38
Co-authors: H.Y. Guo, A.L. Hoffman, R.D. Milroy J.A. Grossnickle, A.Tankut, G.C. Vlases
RPPL, University of Washington
14700 NE 95TH ST, SUITE 100
Redmond, WA 98052
The TCS facility has demonstrated the robust ability to form and sustain FRCs in steady-state using Rotating Magnetic Fields (RMF). In past experiments, the plasma density was largely set by the RMF parameters, but the temperature was severely limited by impurity radiation. Since the FRC is a diamagnetic entity, its peak pressure determines its external magnetic field. Higher FRC currents, magnetic fields, and poloidal fluxes can thus be obtained, with the same RMF parameters, simply by reducing impurity influxes and raising the plasma temperature.
TCS/upgrade has been built with a clean, bakeable vacuum system and active means for the control of impurities. This should allow for the study of RMF current drive physics in a more fusion relevant regime. In particular, it will allow the impact of the RMF on the FRC's energy confinement to be addressed, an issue previously masked by the high radiation levels.
TCSU Improvements include replacing O-ring sealed flanges with wire seals, development of UHV compatible high temperature seals to bond extremely large quartz tubes to stainless chambers, heater blanket installation, glow discharge cleaning, and Ti gettering or other wall conditioning. Physical vapor deposition tantalum films have been applied to protect all components where plasma contact is likely. Extensive testing using an electron microprobe and various spectroscopic techniques have been performed to establish appropriate UHV surface preparation methods suitable for University scale labs. Results from initial operation of TCSU will be presented.