Initial Deuterium Confinement Studies in DIII-D Tokamak: DIII-D Milestone Report (Number Sign) 58.

摘要

The operational space of DIII-D has been extended to include high current, high power deuterium neutral beam heating of deuterium discharges in both the single null and double null configurations. Recent completion of the neutron shielding of the DIII-D facility has allowed operation in these new parameter regimes while maintaining a low neutron dose at the site boundary. The plasma current and neutral beam power ranges with D(degree) (yields) D(sup +) operation have been extended to P(sub T) (le) 12 MW and I(sub p) (le) 2.5 MA. Comparison of H-mode discharges in pure H with those in pure D indicates a continuing superior confinement in deuterium for values of q (ge) 3; however at lower values of q the confinement becomes similar. Analysis of the energy confinement in this regime has shown no major differences in current or power scaling compared to H(degree) (yields) D(sup +) operation. Energy confinement during the ELMing phase of D(degree) (yields) D(sup +) H-mode discharges scales linearly with the plasma current and deteriorates with neutral beam power. Recent, ongoing time dependent analysis of discharges with long ELM-free periods following the L to H transition indicate that the energy confinement time may be independent of power so that power degradation may be a manifestation of ELMs. 1 ref., 5 figs.