First EMC3-eIRENE simulations with divertor legs of LHD in realistic device geometry

An extended mesh system for EMC3-EIRENE has been developed to simulate peripheral plasma including the ergodic and the divertor leg regions of LHD. Both the open and the closed divertor configurations are available. A series of simulations for 8MW input power, five different electron densities at the LCFS (last closed flux surface) and the open/closed configurations were carried out. Approximately 10 times larger neutral pressure was observed under the dome structure compared with the open configuration, which is in good agreement with experimental measurements. In the case of the closed configuration, the leg regions have a large contribution of ionization to hydrogen recycling. In the case of high density discharges, however, electron temperature in the legs becomes low and the major contribution of ionization moves to the ergodic region. Significant influence of configurations is observed in the inboard side of LHD, where closed divertor components are installed but little influence is seen near the LCFS. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)