title: Energy confinement time and heat transport in initial neutral beam heated plasmas on the large helical device
abstract: The confinement characteristics of large net-current-free plasmas heated by neutral-beam injection have been investigated in the Large Helical Device (LHD). A systematic enhancement in energy-confinement times from the scaling derived from the medium-sized heliotron/torsatron experiments have been observed, which is attributed to the edge pedestal. The core confinement is scaled with the Bohm term divided by the square root of the gyro radii. The comparative analysis using a dimensionally similar discharge in the Compact Helical System indicates gyro-Bohm dependence in the core and transport improvement in the edge region of LHD plasmas.
authors.affiliation: National Institute for Fusion Science, Toki, Gifu 509-5292, Japan.
authors.initials: H
authors.lastname: Yamada
authors.initials: KY
authors.lastname: Watanabe
authors.initials: S
authors.lastname: Sakakibara
authors.initials: S
authors.lastname: Murakami
authors.initials: M
authors.lastname: Osakabe
authors.initials: O
authors.lastname: Kaneko
authors.initials: K
authors.lastname: Narihara
authors.initials: K
authors.lastname: Tanaka
authors.initials: K
authors.lastname: Ida
authors.initials: T
authors.lastname: Minami
authors.initials: M
authors.lastname: Goto
authors.initials: H
authors.lastname: Idei
authors.initials: S
authors.lastname: Inagaki
authors.initials: S
authors.lastname: Kado
authors.initials: K
authors.lastname: Kawahata
authors.initials: A
authors.lastname: Komori
authors.initials: S
authors.lastname: Kubo
authors.initials: J
authors.lastname: Miyazawa
authors.initials: T
authors.lastname: Morisaki
authors.initials: S
authors.lastname: Morita
authors.initials: H
authors.lastname: Nakanishi
authors.initials: S
authors.lastname: Ohdachi
authors.initials: N
authors.lastname: Ohyabu
authors.initials: Y
authors.lastname: Oka
authors.initials: BJ
authors.lastname: Peterson
authors.initials: R
authors.lastname: Sakamoto