title: Transition between internal transport barriers with different temperature-profile curvatures in JT-60U Tokamak plasmas.
abstract: A spontaneous transition phenomena between two states of a plasma with an internal transport barrier (ITB) is observed in the steady-state phase of the magnetic shear in the negative magnetic shear plasma in the JT-60U tokamak. These two ITB states are characterized by different profiles of the second radial derivative of the ion temperature inside the ITB region (one has a weak concave shape and the other has a strong convex shape) and by different degrees of sharpness of the interfaces between the L mode and the ITB region, which is determined by the turbulence penetration into the ITB region.
authors.affiliation: National Institute for Fusion Sciences, Toki, Gifu, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ida
authors.forename: Y
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: H
authors.initials: H
authors.lastname: Takenaga
authors.forename: N
authors.initials: N
authors.lastname: Oyama
authors.forename: K
authors.initials: K
authors.lastname: Itoh
authors.forename: M
authors.initials: M
authors.lastname: Yoshinuma
authors.forename: S
authors.initials: S
authors.lastname: Inagaki
authors.forename: T
authors.initials: T
authors.lastname: Kobuchi
authors.forename: A
authors.initials: A
authors.lastname: Isayama
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Fujita
authors.forename: G
authors.initials: G
authors.lastname: Matsunaga
authors.forename: Y
authors.initials: Y
authors.lastname: Koide
authors.forename: M
authors.initials: M
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Ide
authors.forename: Y
authors.initials: Y
authors.lastname: Kamada