Effects of Radially Sheared Electric Field on Turbulence Reduction Analyzed with End-Loss Analysing Systems

Mafumi HIRATA; Teruji CHO; Junko KOHAGURA; Tomoharu NUMAKURA; Serina KIMINAMI; Marie ITO; Naoyuki MORIMOTO; Katsuaki HIRAI; Tooru YAMAGISHI; Toshinori IKUNO; Shohei NAMIKI; Yoshiaki MIYATA; Ryutaro MINAMI; Kazuo OGURA; Takashi KONDOH; Tsuyoshi KARIYA; Tsuyoshi IMAI; Syoichi MIYOSHI

doi:10.1585/pfr.2.S1077

Regular Articles

Effects of Radially Sheared Electric Field on Turbulence Reduction Analyzed with End-Loss Analysing Systems

Mafumi HIRATA, Teruji CHO, Junko KOHAGURA, Tomoharu NUMAKURA, Serina KIMINAMI, Marie ITO, Naoyuki MORIMOTO, Katsuaki HIRAI, Tooru YAMAGISHI, Toshinori IKUNO, Shohei NAMIKI, Yoshiaki MIYATA, Ryutaro MINAMI, Kazuo OGURA, Takashi KONDOH, Tsuyoshi KARIYA, Tsuyoshi IMAI, Syoichi MIYOSHI

Author information

Mafumi HIRATA
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Teruji CHO
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Junko KOHAGURA
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Tomoharu NUMAKURA
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Serina KIMINAMI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Marie ITO
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Naoyuki MORIMOTO
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Katsuaki HIRAI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Tooru YAMAGISHI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Toshinori IKUNO
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Shohei NAMIKI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Yoshiaki MIYATA
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Ryutaro MINAMI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Kazuo OGURA
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
Takashi KONDOH
Japan Atomic Energy Agency, Naka, Ibaraki 311-0193, Japan
Tsuyoshi KARIYA
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Tsuyoshi IMAI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan
Syoichi MIYOSHI
Plasma Research Center, University of Tsukuba, Ibaraki 305-8577, Japan

Keywords: tandem mirror, radially sheared electric field, electron-cyclotron heating, transport-barrier, end-loss analyzer

JOURNAL FREE ACCESS

2007 Volume 2 Pages S1077

DOI https://doi.org/10.1585/pfr.2.S1077

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Abstract

Mirror devices, having open-ended regions, provide intrinsic important advantages in terms of the control of radial-potential or E_r shear profiles on the basis of axial particle loss control for ambipolar potential formation. From the viewpoint of the mechanism investigation of radially localized transport-barrier formation, an idea of off-axis-resonant electron-cyclotron heating (ECH) is proposed and applied in the tandem mirror GAMMA 10, by the use of the aforementioned intrinsic advantage of mirror devices. The off-axis ECH produces a cylindrical layer with energetic electrons and facilitates the formation for a localized bumped ambipolar potential with a strong shear of radial electric fields E_r. Remarkable effects of dE_r/dr on the suppression of turbulent fluctuations with plasma confinement improvement are found by the use of signals of end-loss currents flowing from the central cell as well as the central-cell soft x ray. In association with the reduction of the fluctuations due to strong E_r shear formation, increases in ion and electron temperatures are found.

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