Plasma and Fusion Research

Volume 15, 1202054 (2020)

Rapid Communications

Measurement of Radial Correlation Lengths of Electron Density Fluctuations in Heliotron J Using O-Mode Reflectometry
Niels SMITH, Kazunobu NAGASAKI1), Josefine H.E. PROLL, Hiroyuki OKADA1), Takashi MINAMI1), Shin-ichiro KADO1), Shinji KOBAYASHI1), Shinsuke OHSHIMA1), Shigeru KONOSHIMA1), Tohru MIZUUCHI1), Yuji NAKAMURA2), Akihiro ISHIZAWA2), Tsuyoshi TOMITA2), Takeshi FUKUDA3) and Yasuto KONDO3)
Science and Technology of Nuclear Fusion, Department of Applied Physics, Eindhoven University of Technology (TU/e), 5600 MB Eindhoven, The Netherlands
1)
Institute of Advanced Energy, Kyoto University, Uji 611-0011, Japan
2)
Graduate School of Energy Science, Kyoto University, Uji 611-0011, Japan
3)
Graduate School of Engineering, Osaka University, Suita 565-0871, Japan
(Received 30 April 2020 / Accepted 8 June 2020 / Published 6 August 2020)

Abstract

The radial correlation length Lr of electron density fluctuations has been measured using a two-channel O-mode reflectometer system in the helical-axis fusion plasma experimental device Heliotron J. The experimental results show that Lr is around 1.4 ± 0.7 mm in three different magnetic field bumpiness configurations (i.e. low, medium and high) for the low-density electron cyclotron heating (ECH) discharges. In high-density neutral beam injection (NBI) discharges with HIGP and pellet injection, Lr is found to be around 1 ± 0.2 mm.

Keywords

O-mode reflectometry, radial correlation length, electron density fluctuation, Heliotron J, turbulent transport

DOI: 10.1585/pfr.15.1202054

Full Text

PDF format (458Kbytes) PDF Download

References

  • [1] F. Fernández-Marina et al., Nucl. Fusion 54, 072001 (2014).
  • [2] J. Schirmer et al., Plasma Phys. Control. Fusion 49, 1019 (2007).
  • [3] M. Wakatani et al., Nucl. Fusion 40, 569 (2000).
  • [4] T. Obiki et al., Nucl. Fusion 41, 833 (2001).
  • [5] Y. Kondo et al., Plasma Fusion Res. 15, 2402064 (2020).
  • [6] E. Blanco and T. Estrada, Plasma Phys. Control. Fusion 55, 125006 (2013).