[Table of Contents]

Plasma and Fusion Research

Volume 5, S1049 (2010)

Regular Articles

Experimental Study of Slow Cyclotron Maser Operation in Weakly Relativistic Region
Kiyoshi BANSHO, Kazuo OGURA, Hiroaki OE, Yusuke KAZAHARI, Hiroshi IIZUKA, Akira SUGAWARA, Takashi SHIMOZUMA1), Sakuji KOBAYASHI1) and Kohji OKADA1)
Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan
(Received 8 January 2009 / Accepted 3 August 2009 / Published 26 March 2010)

Abstract

Studies of slow cyclotron maser operation of a slow-wave device are presented. The beam voltage is weakly relativistic, less than 100 kV. The slow-wave structure is a periodically corrugated oversized waveguide for K-band operation. When using rectangular corrugation having a relatively small ratio of corrugation width to periodic length of about 20 %, the dispersion curve near the upper cut-off becomes flat and second harmonic slow cyclotron maser operation is observed in the low-energy region near 30 kV. Another type of combined resonance of Cherenkov and slow cyclotron interaction is also demonstrated in which an absolute instability is driven by the slow cyclotron interaction. By using sinusoidal corrugation and rectangular corrugation having a 50 % ratio of corrugation width to periodic length, amplification effects due to the fundamental and second harmonic slow cyclotron interactions are observed.

Keywords

slow cyclotron maser, Cherenkov interaction, weakly relativistic beam, periodic corrugation, slowwave device

DOI: 10.1585/pfr.5.S1049

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This paper may be cited as follows:

Kiyoshi BANSHO, Kazuo OGURA, Hiroaki OE, Yusuke KAZAHARI, Hiroshi IIZUKA, Akira SUGAWARA, Takashi SHIMOZUMA, Sakuji KOBAYASHI and Kohji OKADA, Plasma Fusion Res. 5, S1049 (2010).