THE EFFECTS OF CHROMIUM AND TITANIUM GETTERING ON THE OPERATION OF THE ADVANCED-TOROIDAL-FACILITY

[摘要] Plasmas in the Advanced Toroidal Facility (ATF), an l = 2 torsatron with 12 field periods, are produced by 200-400 kW of electron cyclotron heating (ECH) and up to 1.5 MW of neutral-beam injection (NBI). The characteristics of the plasmas are sensitive to the type of wall conditioning employed. A progression of techniques, beginning with glow discharge cleaning and baking and evolving to getting with chromium and titanium, has significantly reduced the low-Z impurity content, lowered the fraction of radiated power, and permitted improved control over the electron density. As a result, plasma-parameters and machine performance have been enhanced significantly. The maximum values achieved for stored energy, line-averaged density, and confinement times are 28 kJ, 1.2 x 10(20) m-3, and 25 ms. These parameters are comparable to those obtained in the ISX-B tokamak. In addition, with titanium gettering, quasisteady operation for 200 ms of neutral beam injection has been obtained without the collapses that characterized earlier periods of operation.

[发布日期] 1990-12-01

[效力级别]  Proceedings Paper