Observation of the H-mode in ohmically heated divertor discharges on DIII-D

On DIII-D, periods of improved particle and energy confinement have been observed in low q, low B T divertor discharges with Ohmic heating alone. The Ohmic H-mode has characteristics similar to those of the H-mode produced by auxiliary heating. In the Ohmic H-mode the energy confinement time can have values near those predicted by Neo-ALCATOR scaling and a factor of two above those of non-H-mode Ohmic discharges at similar densities. These observations indicate that the H-mode is not limited to an improvement in confinement over that of the L-mode in auxiliary heating discharges.