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Observation of Ion Heating Using the Difference Frequency of Two ICRF Waves in GAMMA 10/PDX

Hiroki KAYANO, Seowon JANG, Mafumi HIRATA, Naomichi EZUMI, Hibiki YAMAZAKI, Kairi SUGATA, Takumi AIZAWA, Daichi NOGUCHI, Doyeon KIM, Yudai SUGIMOTO, Reina MATSUURA, Ryuya IKEZOE¹⁾, Masayuki YOSHIKAWA, Makoto ICHIMURA and Mizuki SAKAMOTO

Plasma Research Center, University of Tsukuba, Tsukuba 305-8577, Japan

1)

Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan

(Received 24 November 2020 / Accepted 20 December 2020 / Published 12 March 2021)

Abstract

GAMMA 10/PDX is a linear plasma confinement device that mainly uses slow waves in ion cyclotron range of frequencies (ICRF) for heating, and it can achieve a high ion temperature that is in the range of several keV. Although slow waves are effective for ion heating, it is difficult to excite them with antennas at high densities, such as those over 10¹⁹ m⁻³. In this study, we considered a way to excite a slow waves using the frequency difference of input waves. Two fast waves having different frequencies, which are both adequate for high-density plasma, were applied with antennas to excite a slow wave as a difference-frequency wave between the fast waves. As a result, the excitation of difference-frequency waves inside the plasma was confirmed from magnetic probe and reflectometry measurements, and an increase in diamagnetism was also observed. These results firstly demonstrate the possibility of slow-wave heating using a DF wave in a high-density linear plasma, where direct slow-wave heating is not feasible.

Copyright (c) 2021 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

ICRF, ion heating, slow wave, difference-frequency wave, wave excitation, high density, shielding effect, mirror plasma

DOI: 10.1585/pfr.16.2402045

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References

• [1] N. Ohno, Plasma Phys. Control. Fusion 59, 034007 (2017).
• [2] M. Ichimura et al., Plasma Phys. Reports 28, 727 (2002).
• [3] Y. Nakashima et al., Nucl. Fusion 57, 116033 (2017).
• [4] M. Sakamoto et al., Nucl. Mater. Energy 12, 1004 (2017).
• [5] R. Ikezoe et al., Plasma Fusion Res. 14, 2402003 (2019).
• [6] J. Rapp et al., Nucl. Fusion 57, 116001 (2017).
• [7] C.J. Beers et al., Phys. Plasmas 25, 013526 (2018).
• [8] M. Ichimura et al., J. Plasma Fusion Res. SERIES 8, 893 (2009).
• [9] R. Sekine et al., Plasma Fusion Res. 14, 2402011 (2019).
• [10] A. Fasoli et al., Nucl. Fusion 36, 258 (1996).
• [11] K. Sassenberg et al., Nucl. Fusion 50, 052003 (2010).
• [12] S. Sumida et al., Fusion Sci. Technol. 68, 136 (2017).
• [13] R. Ikezoe et al., Fusion Sci. Technol. 68, 63 (2017).
• [14] M. Inutake et al., Phys. Rev. Lett. 65, 27 (1990).
• [15] F.J. Paoloni, Phys. Fluids 18, 640 (1975).
• [16] H. Hojo et al., Jpn. J. Appl. Phys. 32, 3287 (1993).