TY - JOUR
T1 - Effects of radial electric field and its shear on low-frequency fluctuations in the QT-U device
AU - Yoshinuma, Mikirou
AU - Ando, Akira
AU - Sato, Noriyoshi
AU - Inutake, Masaaki
AU - Kaneko, Toshiro
AU - Hattori, Kunihiko
AU - Hatakeyama, Rikizo
PY - 2001/1/1
Y1 - 2001/1/1
N2 - 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.
AB - 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.
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M3 - Conference article
AN - SCOPUS:0035079339
SN - 1536-1055
VL - 39
SP - 191
EP - 194
JO - Fusion Science and Technology
JF - Fusion Science and Technology
IS - 1 T
T2 - International Conference on Open Magnetic Systems for Plasma Confinement
Y2 - 3 July 2000 through 6 July 2000
ER -