Spatial structure of low-frequency fluctuations throughout the transition of poloidal flow velocity in edge plasmas of LHD

C. Moon, T. Kobayashi, K. Ida, T. Tokuzawa, C. Hidalgo, M. Yoshinuma, K. Ogawa, K. Itoh, A. Fujisawa

Research output: Contribution to journalArticle

Abstract

It is observed that a low-frequency (∼2 kHz) density fluctuation is excited in a transition of the poloidal flow velocity (Vθ) in the edge magnetic stochastic region of the Large Helical Device plasmas. Furthermore, it is found that the propagation velocity becomes approximately zero in the proximity of the appearance region of the low-frequency fluctuation by using the edge multichannel microwave Doppler reflectometer system. In particular, the low-frequency fluctuation is considered to be transmitted in both directions (inward and outward) away from the excitation position of the fluctuation, which behaves as the precursor of a magnetic fluctuation burst. Afterward, the edge H α signal intensity is sharply increased.

Original languageEnglish
Article number092302
JournalPhysics of Plasmas
Volume26
Issue number9
DOIs
Publication statusPublished - Sep 1 2019

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Spatial structure of low-frequency fluctuations throughout the transition of poloidal flow velocity in edge plasmas of LHD'. Together they form a unique fingerprint.

  • Cite this