title: Stationary multifaceted asymmetric radiation from the edge and improved confinement mode in a superconducting tokamak.
abstract: Stationary multifaceted asymmetric radiation from the edge (MARFE) is studied by gas-puffing feedback control according to an empirical MARFE critical density ( approximately 1.8 x 10(13) cm(-3)) in the HT-7 Ohmic discharges (where the plasma current I(p) is about 170 kA, loop voltage V(loop)=2-3 V, toroidal field B(T)=1.9 T, and Z(eff)=3-4). It is observed that an improved confinement mode characterized by D(alpha) line emissions drops and the line-averaged density increase is triggered in the stationary MARFE discharges. The mode is not a symmetric "detachment" state, because the quasi-steady-state poloidally asymmetric radiation (e.g., C III line emissions) still exists. This phenomenon has not been predicted by the current MARFE theory.
authors.affiliation: Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China. xgao@mail.ipp.ac.cn
authors.forename: X
authors.initials: X
authors.lastname: Gao
authors.forename: J K
authors.initials: JK
authors.lastname: Xie
authors.forename: Y X
authors.initials: YX
authors.lastname: Wan
authors.forename: K
authors.initials: K
authors.lastname: Ushigusa
authors.forename: B N
authors.initials: BN
authors.lastname: Wan
authors.forename: S Y
authors.initials: SY
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: G L
authors.initials: GL
authors.lastname: Kuang