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Data Structure for LHD Plasmas in the International Stellarator/Heliotron Profile Database
No full text3D Divertor Transport Study of the Local Island Divertor Configuration in the Large Helical Device
No full textThe divertor/SOL transport of the Local Island Divertor (LID) configuration in the Large Helical Device (LHD) is studied. Since the LID configuration has an inherent three dimensional magnetic structure, the 3D edge transport code, EMC3-EIRENE, is applied in order to elucidate the 3D divertor transport physics. The main observations reported here are: 1. The effective temperature cooling due to the integrated perpendicular energy loss along the long connection length. 2. The significant plasma flow acceleration caused by the upstream source that is attributed to the geometrical significance of the LID configuration. 3. The effect of the flow acceleration on the impurity screening considering a parallel transport along the SOL. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Searching for O-X-B mode-conversion window with monitoring of stray microwave radiation in LHD
Get PDFIn the Large Helical Device, the stray microwave radiation is monitored by using so-called sniffer probes during electron cyclotron heating. In monitoring the stray radiation, we changed the microwave beam injection angle and search the O-X-B mode-conversion window to excite electron Bernstein waves (EBWs). When the microwave beam is injected toward the vicinity of the predicted O-X-B mode-conversion window, the electron temperature rises in the central part of overdense plasmas. In that case, the stray radiation level near the injection antenna becomes low. These results indicate that monitoring the stray radiation near the injection antenna is helpful in confirming the effectiveness of excitation of EBWs simply without precise analysis.journal articl
Divertor transport study in the large helical device
Get PDFThe edge transport properties in LHD have been investigated in order to clarify divertor/SOL functions of heliotron type device. The momentum loss, mainly through friction of counter-flows induced by ergodic field lines, breaks the pressure conservation along flux tubes. This prevents high recycling regime even at high density operation, (n) over bar similar to 7 x 10(19) m(-3). The momentum loss is found to be larger than in W7-AS. This is because of the higher ratio of perpendicular and parallel transport scale length, similar to 10(-4), in the ergodic layer, which enhances the friction between counter-flows more than in the island divertor. In the heliotron configuration, a large temperature drop from LCFS to divertor by an order of magnitude is easily realized due to the long connection length in the ergodic layer. This is certainly a favourable feature for future reactors in terms of reduction of damage on the divertor plate. (c) 2007 Elsevier B.V. All rights reserved
Control of the radial electric field shear by modification of the magnetic field configuration in LHD
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Model prediction of impurity retention in stochastic magnetic boundary and comparison with edge carbon emission in LHD
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