Two-Dimensional Distribution of Plasma Electric Potential in the T-10 Tokamak

Abstract

Heavy ion beam probe (HIBP) is a unique plasma diagnostics that makes it possible to measure the electric potential φ of high-temperature plasma and its fluctuations \(\tilde {\varphi }\), as well as the density \({{\tilde {n}}_{e}}\) and poloidal magnetic field \({{\tilde {B}}_{{{\text{pol}}}}}\) fluctuations. Position of the point of performing measurements in the plasma vertical cross-section depends on the beam energy and angle of its entrance into the plasma. The variation of these two parameters makes it possible to construct a two-dimensional (2D) detector grid, which covers the domain of possible measurements. The measurement results obtained in the detector grid points provide for constructing 2D distributions of plasma parameters. For the OH and ECRH stages of the T-10 tokamak shots, 2D distributions of the plasma electric potential are presented for the regime with the on-axis magnetic field of B_t = 2.2 T, plasma current of I_pl = 230 kA, line-average density of \({{\bar {n}}_{e}}\)≈ 1.1 × 10¹⁹ m^–3 and off-axis ECRH power of P_ECRH = 1.7 MW.