Determination of the Alfvén oscillation location in the TUMAN-3M tokamak plasma

The Alfvén oscillations have been studied in ohmically heated deuterium discharges with LH-transition in the TUMAN-3M tokamak in order to clarify their location in a plasma column. The Alfvén oscillation location was determined by comparison of the oscillation frequency measured with magnetic probes and that calculated from local density assuming the typical dispersion relation for Alfvén waves $f=(2\pi)^{-1}k_\parallel v_{A}$, where $v_A$ is the Alfvén velocity and $k_\parallel$ is the the parallel wave number in the direction of the magnetic field. It was found that they are localized in central part of plasma column inside $r/a<$ 0.5 region. Candidate sets of mode numbers have been determined.