| 1 | MHD Instabilities and Their Effects on Plasma Confinement in Large Helical Device Plasmas with Intense Neutral Beam Injection显示文摘MHD stability of the Large Helical Device (LHD) plasmas produced with intense neutral beam injection is experimentally studied. When the steep pressure gradient near the edge is produced through L-H transition or linear density ramp experiment, interchange-like MHD modes whose rational surface is located very close to the last closed flux surface are strongly excited in a certain discharge condition and affect the plasma transport appreciably. In NBI-heated plasmas produced at low toroidal field, various Alfvén eigenmodes are often excited. Bursting toroidal Alfvén egenmodes excited by the presence of energetic ions induce appreciable amount of energetic ion loss, but also trigger the formation of internal and edge transport barriers. | K.Toi S.Ohdachi S.Yamamoto S.Sakakibara K.Y.Watanabe N.Nakajima X.Ding J.Li S.Morita K.Narihara K.Tanaka T.Tokuzawa H.Yamada Q.Yang | 2004 | Plasma Science and Technology2004，6，3： | 3 |
| 2 | Magnetic Configuration Effects on Fast Ion Losses Induced by Fast Ion Driven Toroidal Alfvén Eigenmodes in the Large Helical Device显示文摘Beam-ion losses induced by fast-ion-driven toroidal Alfvén eigenmodes (TAE) were measured with a scintillator-based lost fast-ion probe (SLIP) in the large helical device (LHD). The SLIP gave simultaneously the energy E and the pitch angle χ=arccos(v // /v) distribution of the lost fast ions. The loss fluxes were investigated for three typical magnetic configurations of R ax vac =3.60 m, 3.75 m, and 3.90 m, where R ax vac is the magnetic axis position of the vacuum field. Dominant losses induced by TAEs in these three configurations were observed in the E/χ regions of 50~190 keV/40°, 40~170 keV/25°, and 30~190 keV/30°, respectively. Lost-ion fluxes induced by TAEs depend clearly on the amplitude of TAE magnetic fluctuations, R ax vac and the toroidal field strength Bt . The increment of the loss fluxes has the dependence of (bTAE /Bt ) s . The power s increases from s = 1 to 3 with the increase of the magnetic axis position in finite beta plasmas. | K.OGAWA M.ISOBE K.TOI F.WATANABE D.A.SPONG A.SHIMIZU M.OSAKABE D.S.DARROW S.OHDACHI S.SAKAKIBARA LHD Experiment Group | 2012 | Plasma Science and Technology2012，14，4： | 0 |
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