JT-60U MONTHLY SUMMARY
After the divertor modification, plasma operation condition in JT-60U is
to be re-optimized. A detailed study has been started on the discharge sequence
and plasma configuration for high confinement modes suitable for the new
divertor. It has been started to produce the new database of plasma shape
and position required for the real time feedback control of JT-60U discharges
with the new divertor.
Systematic study have progressed on transport barriers of high confinement
modes such as H-mode, high-beta-p mode and reversed shear mode. Concerning
the edge transport barrier in H-mode, width of the edge pedestal is proportional
to the poloidal gyro radius of thermal ion in the ELM-free phase. Whereas,
in the ELMy phase, the width is much wider than that in the ELM-free phase
and is affected by ELM activity.
Operation schedule for three weeks in January and February was discussed
and determined. Improvement of the current drive performance with the negative-ion-based
neutral beam (N-NB) is the highest priority in physics issues. Parametric
dependence of current drive performance with the N-NB was investigated with
the ACCOME code for next run scheduled in February '97. The N-NB power over
3 MW with the energy of 350-400 keV will be expected in the run after the
aging operation in January '97.
BOUNDARY AND STEADY STATE OPERATION PHYSICS
For the divertor modification, technical review committee meetings were
held to supervise the new divertor diagnostics such as the reciprocating
probe, the divertor interferometer etc. "Radiative divertor in the
reversed shear plasmas in JT-60U" and "Impurity modeling in JT-60U"
were presented from JT-60U in the meeting on "Interaction between gas
and plasma" at Nagoya, 5-6 December.