Plasma and Fusion Research

Volume 3, S1028 (2008)

Regular Articles

Density Control by Second Harmonic X-Mode ECRH in LHD

Shin KUBO, Takashi SHIMOZUMA, Kenji TANAKA, Teruo SAITO¹⁾, Yoshinori TATEMATSU¹⁾, Yasuo YOSHIMURA, Hiroe IGAMI, Takashi NOTAKE¹⁾, Shigeru INAGAKI²⁾, Naoki TAMURA and LHD Experimental Group

National Institute for Fusion Science, Toki 509-5292, Japan
1): Research Center for Development of FIR Region, Fukui University, Fukui 910-8507, Japan
2): Research Institute of Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan

(Received 21 November 2007 / Accepted 27 March 2008 / Published 4 August 2008)

Abstract

Density clamping or pump-out phenomena is observed both in tokamaks and helical systems during additional heating, particularly high power density heating as electron cyclotron resonance heating (ECRH). Enhanced electron convective flux induced by a perpendicular acceleration of electrons is one of the candidates of the mechanism of these phenomena. The mechanism of the enhancement of the electron flux is investigated experimentally by comparing the density profile evolutions due to second harmonic X (X2) mode ECRH at the ripple top and bottom. The result suggests that ECRH-induced electron flux is one of the dominant mechanisms of density clamping, which can be used as a powerful tool for controlling the particles and the heat transport.

Keywords

ECRH, density pump out, density control, direct loss, radial electric field

DOI: 10.1585/pfr.3.S1028

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References

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This paper may be cited as follows:

Shin KUBO, Takashi SHIMOZUMA, Kenji TANAKA, Teruo SAITO, Yoshinori TATEMATSU, Yasuo YOSHIMURA, Hiroe IGAMI, Takashi NOTAKE, Shigeru INAGAKI, Naoki TAMURA and LHD Experimental Group, Plasma Fusion Res. 3, S1028 (2008).