TY - JOUR
T1 - First ohmic discharge assisted with RF power in QUEST spherical tokamak
AU - Mitarai, Osamu
AU - Nakamura, Kazuo
AU - Tashima, Saya
AU - Hasegawa, Makoto
AU - Idei, Hiroshi
AU - Sakamoto, Mizuki
AU - Hanada, Kazuaki
AU - Zushi, Hideki
AU - Sato, Kohnosuke
AU - Ishiguro, Masaki
AU - Liu, Hai Qing
AU - Higashizono, Yuta
AU - Higashijima, Aki
AU - Nakashima, Hisatoshi
AU - Kawasaki, Shoji
AU - Takase, Yuichi
AU - Maekawa, Takashi
AU - Nishino, Nobuhiro
PY - 2011
Y1 - 2011
N2 - Ohmic plasma currents of up to 17 kA with a discharge duration of 0.32 s have been obtained in the Kyushu University Experiment with Steady-State Spherical Tokamak (QUEST) with the help of electron cyclotron wave (ECW) and cancellation coils (CCs). The CCs, originally installed to create a field null in the plasma breakdown phase, are essential for producing plasma current in QUEST. Although the ohmic coil current is initially biased and then reduced completely to zero to induce the plasma current in 15-20 ms, we demonstrate that the flat top of the plasma current exceeding 20 ms is maintained by the vertical field after the ohmic current is switched off. This type of operation is quite favorable for extending pulsed operation to the steady state by electron Bernstein wave current drive (EBCD).
AB - Ohmic plasma currents of up to 17 kA with a discharge duration of 0.32 s have been obtained in the Kyushu University Experiment with Steady-State Spherical Tokamak (QUEST) with the help of electron cyclotron wave (ECW) and cancellation coils (CCs). The CCs, originally installed to create a field null in the plasma breakdown phase, are essential for producing plasma current in QUEST. Although the ohmic coil current is initially biased and then reduced completely to zero to induce the plasma current in 15-20 ms, we demonstrate that the flat top of the plasma current exceeding 20 ms is maintained by the vertical field after the ohmic current is switched off. This type of operation is quite favorable for extending pulsed operation to the steady state by electron Bernstein wave current drive (EBCD).
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U2 - 10.1585/pfr.6.1402003
DO - 10.1585/pfr.6.1402003
M3 - Article
AN - SCOPUS:84860301319
SN - 1880-6821
VL - 6
JO - Plasma and Fusion Research
JF - Plasma and Fusion Research
IS - 2011
M1 - 1402003
ER -