MAGNETIC PERTURBATION EFFECTS ON BOUNDARY PLASMAS DURING HIGH-POWER LOWER HYBRID CURRENT DRIVE IN TORE SUPRA

Small time-independent magnetic perturbations (deltab(r)), produced with the Tore Supra ergodic divertor coils, have been used to control thermal loads on plasma facing components, current density profiles, the transport of non-Maxwellian particles, and the confinement properties of thermal plasmas during high power (P(LH) less-than-or-equal-to 3.3 MW) lower hybrid current drive (LHCD) discharges. MARFEs with 0.12 less-than-or-equal-to rho(m) = pia2[n(e20]I(p)-1 less-than-or-equal-to 0.22 (i.e., roughly a factor of 3 less than the smallest value of rho(m) previously reported) are obtained during the deltab(r) pulse when P(LH) > 2.0 MW and the edge safety factor is slightly less than 3. These MARFEs generally appear to have the same characteristics as high rho(m) MARFEs and are positionally stable throughout the LHCD+deltab(r) pulse. Steady state conditions in which more than 90% of the total input power is radiated from a 0.15 m wide region near the high-field side wall were obtained.