Alfven frequency sweeping modes in stellarator plasmas with normal and reversed shear rotational transform are modelled using a reduced MHD model. We focus on a TJ-II dynamic discharge in which a sequence of frequency sweeping modes with a frequency sweeping range from 20 kHz to 140 kHz (Melnikov A.V. et al 2014 Nucl. Fusion 54 123002) have been ob…
Alfven Eigenmodes were studied in low magnetic shear flexible heliac TJ-II (B0=0.95 T, =1.5 m, =0.22 m) NBI heated plasmas (PNBI <1.1 MW, ENBI=32 keV) by Heavy Ion Beam Probe (HIBP) [1, 2, 3]. The L-mode hydrogen plasma was investigated at various magnetic configurations with rotational transform t(a)/2