Selective excitation of low frequency drift waves by density modulation and parametric excitation of higher frequency mode.
Excitation of low frequency drift waves in a radial region of a weak density gradient is demonstrated experimentally by strong temporal modulation of the plasma density. Though a parallel electron current can destabilize drift waves throughout the region, we observe mode selection at the resonant location matching the frequency of modulation. Parametric mode-mode interaction among two excited drift modes to destabilize a higher frequency one is reported under the specific condition of the growth rate. Theoretically estimated growth rates fit well with the experiment.
Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064, India.
Subir
S
Biswas
Debjyoti
D
Basu
Rabindranath
R
Pal
Nikhil
N
Chakrabarti