High-Harmonic Fast Wave Heating and Current Drive Results for Deuterium H-Model Plasmas in the National Spherical Torus Experiment.

摘要

A critical research goal for the spherical torus (ST) program is to initiate, ramp-up, and sustain a discharge without using the central solenoid. Simulations of non-solenoidal plasma scenarios in the National Spherical Torus Experiment (NSTX) predict that high-harmonic fast wave (HHFW) heating and current drive (CD) can play an important roll in enabling fully non-inductive (fNI (approx) 1) ST operation. The NSTX fNI (approx) 1 strategy requires 5-6 MW of HHFW power (PRF) to be coupled into a non-inductively generated discharge with a plasma current, Ip (approx) 250-350 kA, driving the plasma into an HHFW H-mode with Ip (approx) 500 kA, a level where 90 keV deuterium neutral beam injection (NBI) can heat the plasma and provide additional CD. The initial approach on NSTX has been to heat Ip (approx) 300 kA, inductively heated, deuterium plasmas with CD phased HHFW power, in order to drive the plasma into an H-mode with fNI (approx).