TY - JOUR
T1 - Spontaneous L-H transitions under marginal hot cathode biasing in the Tohoku University Heliac
AU - Kitajima, S.
AU - Takahashi, H.
AU - Tanaka, Y.
AU - Utoh, H.
AU - Yokoyama, M.
AU - Inagaki, S.
AU - Suzuki, Y.
AU - Nishimura, K.
AU - Shinde, J.
AU - Ogawa, M.
AU - Iwazaki, K.
AU - Aoyama, H.
AU - Okamoto, A.
AU - Shinto, K.
AU - Sasao, M.
PY - 2006/5/1
Y1 - 2006/5/1
N2 - A series of hot cathode biasing experiments with marginal conditions for improved mode transition were carried out in the Tohoku University Heliac (TU-Heliac). Spontaneous transitions were observed accompanied by a delay of a few milliseconds. Transition conditions were explored over a wide operation range. The transition points can be identified clearly and easily in the operation range, because the plasma parameters changed slowly until the spontaneous transition. Although operation conditions were spread over a wide range, poloidal Mach numbers for transitions were concentrated in the range of -Mp = 1-2 and normalized driving forces for poloidal rotation agreed well with the local maximum value of ion viscosity predicted by neoclassical theory. The local maximum of ion viscosity against the poloidal Mach number was found to play a key role in the L-H transition. Marginal hot cathode biasing is suitable to determine the threshold conditions for the L-H transition.
AB - A series of hot cathode biasing experiments with marginal conditions for improved mode transition were carried out in the Tohoku University Heliac (TU-Heliac). Spontaneous transitions were observed accompanied by a delay of a few milliseconds. Transition conditions were explored over a wide operation range. The transition points can be identified clearly and easily in the operation range, because the plasma parameters changed slowly until the spontaneous transition. Although operation conditions were spread over a wide range, poloidal Mach numbers for transitions were concentrated in the range of -Mp = 1-2 and normalized driving forces for poloidal rotation agreed well with the local maximum value of ion viscosity predicted by neoclassical theory. The local maximum of ion viscosity against the poloidal Mach number was found to play a key role in the L-H transition. Marginal hot cathode biasing is suitable to determine the threshold conditions for the L-H transition.
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U2 - 10.1088/0741-3335/48/5A/S24
DO - 10.1088/0741-3335/48/5A/S24
M3 - Article
AN - SCOPUS:34247480205
SN - 0741-3335
VL - 48
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 5 A
ER -