SCALING OF THE SAWTOOTH INVERSION RADIUS AND THE MIXING RADIUS ON DIII-D

In highly elongated DIII-D divertor discharges, it was found that the line integrated X-ray sawtooth inversion radius scales as rinv/a = 1/q95 for a wide range of plasma parameters including low q and high beta discharges. No density or elongation dependence was observed. The sawtooth inversion radius showed little dependence on injected beam power in H-mode discharges at full toroidal field (2.1 T). At lower fields, the sawtooth inversion radius was observed to increase somewhat with increasing input power. Also, it was found that the sawtooth mixing radius scales as rmix/a = 1/q95 + 0.3 and is independent of elongation. © 1990 IOP Publishing Ltd.