[Table of Contents]

Plasma and Fusion Research

Volume 2, 043 (2007)

Regular Articles

Heat- and Particle-Deposition Distribution on Helical Divertor Plates in LHD During Real-Time Magnetic-Axis Swing Operations
Hironori OGAWA, Suguru MASUZAKI1), Tsuguhiro WATANABE1), Tomohiro MORISAKI1), Takashi MUTOH1), Ryuhei KUMAZAWA1), Tetsuo SEKI1), Kenji SAITO1), Yukio NAKAMURA1), Akio KOMORI1), Nobuyoshi OHYABU1) and the LHD experimental group1)
Graduate University for Advanced Studies
1)
National Institute for Fusion Science
(Received 19 June 2007 / Accepted 2 August 2007 / Published 4 October 2007)

Abstract

Investigations of heat- and particle-deposition distributions on helical divertor plates were performed both experimentally and numerically with the Large Helical Device (LHD). The distributions were measured by thermocouples and Langmuir probe arrays embedded in the divertor plates. They are similar to the distribution of field lines with long connection lengths, which are estimated numerically by field-line tracing calculations. Localized heat- and particle-deposition distributions were observed, and were found to be determined primarily by the magnetic-field line structure in the divertor region. They vary depending on the configuration − the intensively loaded areas move with a change of the magnetic configuration. Using this property, a swing of the magnetic axis successfully dispersed the heat and particle loads on the divertor plate during long-pulse discharges. The magnetic-axis swing around a certain magnetic-axis position is found to be very effective in changing the field-line distribution pattern drastically, and thus dispersing the heat load.

Keywords

LHD (Large Helical Device), helical divertor, long-pulse discharge, heat-load dispersion, real-time magnetic-axis swing, field-line tracing calculation

DOI: 10.1585/pfr.2.043

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This paper may be cited as follows:

Hironori OGAWA, Suguru MASUZAKI, Tsuguhiro WATANABE, Tomohiro MORISAKI, Takashi MUTOH, Ryuhei KUMAZAWA, Tetsuo SEKI, Kenji SAITO, Yukio NAKAMURA, Akio KOMORI, Nobuyoshi OHYABU and the LHD experimental group, Plasma Fusion Res. 2, 043 (2007).