Low-frequency fluctuations in a pure toroidal magnetized plasma

A magnetized, low-beta plasma in pure toroidal configuration is formed and extensively studied with ion mass as control parameter. Xenon, krypton and argon plasmas are formed at a fixed toroidal magnetic field of 0.024 T, with a peak density of similar to 10(11) cm(-3), similar to 4 x 10(10) cm (-3) and similar to 2 x 10(10) cm (-3) respectively. The experimental investigation of time-averaged plasma parameter reveals that their profiles remain insensitive to ion mass and suggests that saturated slab equilibrium is obtained. Low-frequency (LF) coherent fluctuations (omega < omega (ci)) are observed and identified as flute modes. Here omega (ci) represents ion cyclotron frequency. Our results indicate that these modes get reduced with ion mass. The frequency of the fluctuating mode decreases with increase in the ion mass. Further, an attempt has been made to discuss the theory of flute modes to understand the relevance of some of our experimental observations.