Effects of radial electric field and its shear on low-frequency fluctuations in the QT-U device

Mikirou Yoshinuma, Akira Ando, Noriyoshi Sato, Masaaki Inutake, Toshiro Kaneko, Kunihiko Hattori, Rikizo Hatakeyama

Research output: Contribution to journalConference articlepeer-review

1 Citation (Scopus)


Radial potential profiles are precisely controlled to vary both radial electric field Er and its shear by using a 10-segmented endplate in an ECR-produced plasma. Observed frequencies and intensities of flute-mode and drift-mode fluctuations depend on the potential profile. The frequencies are Doppler shifted by E × B drift. The flute-mode fluctuation is identified as Kelvin-Helmholtz type instability which is destabilized by strong E × B flow shear. The drift-mode fluctuation is destabilized in the region of small and negative electric field. When the E × B rotation frequency shear is increased with Er being fixed, the drift-mode fluctuations increase once in a weaker shear region, attain its peak at a certain shear and then decrease in the strong shear region. This behavior suggests that the rotation frequency shear of net ion drift which is determined from both E × B drift and diamagnetic drift is important for stabilizing the drift mode.

Original languageEnglish
Pages (from-to)191-194
Number of pages4
JournalFusion Technology
Issue number1 T
Publication statusPublished - 2001 Jan 1
EventInternational Conference on Open Magnetic Systems for Plasma Confinement - Tsukuba, Jpn
Duration: 2000 Jul 32000 Jul 6

ASJC Scopus subject areas

  • Engineering(all)


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