The study of the electric potential of magnetically confined fusion plasmas

The paper presents results of the experimental study of plasma electric potential in toroidal systems with magnetic confinement. The study is based on the data of unique diagnostics to study the potential in the core plasmas - Heavy Ion Beam Probing (HIBP), as well as other diagnostics. Paper describes HIBP diagnostic systems for probing the plasma of the tokamak T-10 and the stellarator TJ-II and the results of the measurements of stationary potential profiles and oscillations in the form of quasi-monochromatic and broadband fluctuations. The results of studies of turbulent particle flux, fluctuations of density and poloidal magnetic field are presented as well. The properties of geodesic acoustic modes of plasma oscillations and Alfvén Eigenmodes excited by fast particles of Neutral Beam Injection heating are described. A wide range of the operational modes of tokamak and stellarator with different magnetic configurations and methods of plasma heating was investigated. General regularities in the behavior of the electric potential and turbulence in a magnetized plasma were revealed.