TY - JOUR
T1 - Progress of ECRH by EBW in over-dense plasmas and controlling the confinement regime by ECCD with high power launching in LHD
AU - Igami, H.
AU - Yoshimura, Y.
AU - Takahashi, H.
AU - Shimozuma, T.
AU - Kubo, S.
AU - Idei, H.
AU - Nishiura, M.
AU - Ogasawara, S.
AU - Makino, R.
AU - Ohdachi, S.
AU - Ida, K.
AU - Yoshinuma, M.
AU - Ido, T.
AU - Shimizu, A.
AU - Tamura, N.
AU - Inagaki, S.
AU - Mutoh, T.
PY - 2012
Y1 - 2012
N2 - In the large helical device (LHD), fundamental electron cyclotron resonance heating (ECRH) by the electron Bernstein wave (EBW) excited via the ordinary-extraordinary-EBW (O-X-B) mode conversion process was performed with high power (∼1MW) launching. Profiles of increase of the electron temperature (Te) and the soft X-ray signals during the power injection suggest power absorption in the core region. Effects of the local modification of the rotational transform ι/2π(=1/q) by electron cyclotron current drive (ECCD) on the formation and sustainment of the electron internal transport barrier (e-ITB) was investigated for the first time. Co ECCD raised ι/2π close to 0.5 in the core region and caused the flattening of the Te profile. Additional ECRH power is required to form the e-ITB. On the contrary, counter (cntr.) ECCD separates ι/2π from 0.5 in the core region and avoids the flattening of the Te profile. The e-ITB can be formed and sustained without additional ECRH. Analysis of the heat pulse transport with use of the modulation ECRH (MECH) shows the good confinement region extends to the ι/2π =0.5 rational surface in the case of cntr. ECCD.
AB - In the large helical device (LHD), fundamental electron cyclotron resonance heating (ECRH) by the electron Bernstein wave (EBW) excited via the ordinary-extraordinary-EBW (O-X-B) mode conversion process was performed with high power (∼1MW) launching. Profiles of increase of the electron temperature (Te) and the soft X-ray signals during the power injection suggest power absorption in the core region. Effects of the local modification of the rotational transform ι/2π(=1/q) by electron cyclotron current drive (ECCD) on the formation and sustainment of the electron internal transport barrier (e-ITB) was investigated for the first time. Co ECCD raised ι/2π close to 0.5 in the core region and caused the flattening of the Te profile. Additional ECRH power is required to form the e-ITB. On the contrary, counter (cntr.) ECCD separates ι/2π from 0.5 in the core region and avoids the flattening of the Te profile. The e-ITB can be formed and sustained without additional ECRH. Analysis of the heat pulse transport with use of the modulation ECRH (MECH) shows the good confinement region extends to the ι/2π =0.5 rational surface in the case of cntr. ECCD.
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U2 - 10.1051/epjconf/20123202006
DO - 10.1051/epjconf/20123202006
M3 - Conference article
AN - SCOPUS:84883006732
SN - 2101-6275
VL - 32
JO - EPJ Web of Conferences
JF - EPJ Web of Conferences
M1 - 02006
T2 - 17th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2011
Y2 - 7 May 2012 through 10 May 2012
ER -