JT-60U MONTHLY SUMMARY

April 1997


OPERATION AND CONFINEMENT PHYSICS

In the 4th ITER expert meetings on "Confinement and Transport" and "Confinement Database and Modeling", the JT-60 Team reported the results of the power threshold for the H-mode transition, demonstration of ITER-like discharges, ELM behavior and the advanced tokamak scenario including reversed magnetic shear. In particular, effects of wall condition and behavior of neutrals on confinement characteristics were emphasized.

CURRENT DRIVE AND HIGH ENERGY PARTICLE PHYSICS

Following topics were presented as an invited paper in the 12th Topical Conference on Radio Frequency Power in Plasmas, Savannah, April 1-3; 1) Sustainment of a negative magnetic shear configuration for up to 7.5 s, 2) Control of the location of qmin in a negative magnetic shear configuration by LHCD, 3) Combined current drive with LHCD and N-NBCD (350 keV), 4) ICRF heating of negative shear plasmas by changing ICRF/NBI power ratio, 5) Multiple TAE modes inside q=1 surface and 6) Dependence of Antenna voltage limit on plasma shape.

DIVERTOR AND BOUNDARY PHYSICS

The construction of the W-shaped divertor for JT-60U was favorably in progress. Divertor plates, baffle supports and plates and domes were fabricated, and most of CFC tiles and graphite tiles were set on these plates by the end of April. The installation of new divertor diagnostics was completed. The divertor operation working group discussed functional tests and operation scenarios for the new divertor system in the first experimental period in June.