Speaker
Dr
Ryuya Ikezoe
(Plasma Research Center, University of Tsukuba)
Description
Slow Alfvén waves in ion cyclotron range of frequencies (ICRF) are a powerful tool to heat ions confined in a mirror field. In spite of its efficient heating effect that has been attained in the central cell of GAMMA 10, there are still unknown characteristics concerning boundary condition, transient variation of heating effect, exact picture of cyclotron damping, and so on. What we need to study these characteristics in detail is a multi-point measurement of the waves inside the hot plasma. We have been developing such a measurement system by using a microwave reflectometer. In addition to the radial profile that is easy to measure with a reflectometer, axial measurements have been achieved by arraying transmitting and receiving horn antennas in the axial direction, which are repeatedly switched in time during a discharge with PIN diode switches [1]. Another transmitting and receiving horn antenna pair was newly added to the system and probing at five cross sections was achieved in a single discharge with time resolution of about 1 ms at each antenna pair position. The time resolution is not determined by electrical characteristic of the system but by the time window required for fluctuation analysis. With the upgraded antenna array, axial variation of wave-induced fluctuation intensity was clearly observed, offering valuable data on wave physics in a hot mirror plasma.
Financial support was received in part from Grants-in-Aid for Young Scientists (B) (Grant No. 15K17797) and from Bidirectional Collaborative Research Program of NIFS (Grant No. NIFS17KUGM132).
[1] R. Ikezoe et al., Rev. Sci. Instrum. 88, 033504 (2017).
Primary author
Dr
Ryuya Ikezoe
(Plasma Research Center, University of Tsukuba)
Co-authors
Mr
Atsuto Tanaka
(Plasma Research Center, University of Tsukuba)
Dr
Junko Kohagura
(Plasma Research Center, University of Tsukuba)
Mr
Junpei Itagaki
(Plasma Research Center, University of Tsukuba)
Mr
Koki Izumi
(Plasma Research Center, University of Tsukuba)
Dr
Mafumi Hirata
(Plasma Research Center, University of Tsukuba)
Dr
Makoto Ichimura
(Plasma Research Center, University of Tsukuba)
Dr
Masayuki Yoshikawa
(University of Tsukuba)
Prof.
Mizuki Sakamoto
(Plasma Research Center, University of Tsukuba)
Mr
Ryo Sekine
(Plasma Research Center, University of Tsukuba)
Mr
Seowon Jang
(Plasma Research Center, University of Tsukuba)
Mr
Shuhei Sumida
(Plasma Research Center, University of Tsukuba)
Mrs
Yoriko Shima
(Plasma Research Center, University of Tsukuba)
Prof.
Yousuke Nakashima
(Plasma Research Center, University of Tsukuba)
Mr
Yushi Kubota
(Plasma Research Center, University of Tsukuba)
