Existence of Fluctuation Depletion Layer in Simple Magnetized Torus

This paper presents an experimental finding of the existence of Fluctuation Depleted Layer (FDL) in the plasma center of BETA, a simple magnetized toroidal device. It is observed that the plasma center is deficient of both coherent and turbulent components of the excited fluctuations. The fluctuations seem to be consistent with the transport characteristics of fluxes of energy, matter and entropy. Consistency check is given by the comparison of predicted FDL from profile of time-averaged plasma parameters with the experimentally determined FDL. This gives an experimental proof that FDL is a consequence of operation of principle of self-consistency in BETA. Self consistency forces spatial profiles of plasma parameters to adjust themselves to profile of fluctuations such that fluxes of energy and matter injected by the source is transported out at the boundaries.