[Table of Contents]

Plasma and Fusion Research

Volume 6, 2401122 (2011)

Regular Articles

Wave Characteristics in the Electron Cyclotron Range of Frequencies in Overdense Plasmas in the Internal Coil Device Mini-RT
Kenichiro UCHIJIMA, Keigo OKABE, Akihiro HONDA, Eiichi YATSUKA, Kiyotake KINJO, Junji MORIKAWA and Yuichi OGAWA
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8568, Japan
(Received 7 December 2010 / Accepted 31 May 2011 / Published 11 August 2011)


In the internal coil device Mini-RT, overdense plasmas have been observed, and heating by electron Bernstein waves (EBWs) is expected. EBWs, which have no cutoff density, are electrostatic-mode waves converted from the electromagnetic mode. To examine mode conversion in Mini-RT experiments, we are attempting to investigate the propagation of waves in the electron cyclotron range of frequencies (ECRF) in overdense plasmas. We injected diagnostic microwaves (typically 1 GHz) into a plasma produced by 2.45 GHz microwaves and directly measured their characteristics by inserting various probing antennas into the plasma with an interference system. Electromagnetic field measurements revealed a long-wavelength mode in the area with lower density than the upper hybrid resonance (UHR) region. In the area with higher density than that of the UHR region, waves having the characteristics of EBWs were observed; namely, short wavelength (∼20 mm), electrostatic mode, longitudinal polarization, and backward wave mode. These results suggest that EBWs were mode converted from electromagnetic waves at the UHR.


overdense plasma, mode conversion, electron bernstein wave, internal coil device, electromagnetic field measurement

DOI: 10.1585/pfr.6.2401122


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This paper may be cited as follows:

Kenichiro UCHIJIMA, Keigo OKABE, Akihiro HONDA, Eiichi YATSUKA, Kiyotake KINJO, Junji MORIKAWA and Yuichi OGAWA, Plasma Fusion Res. 6, 2401122 (2011).