Radial and Vertical Displacement Events of Plasma in the Damavand Tokamak

Abstract

The plasma current in tokamak is under the influence of forces in such a way it tents toward the radial expansion. The forces resulting from external self-induced, internal inductance, thermal energy, and magnetic field fluctuations on the plasma column, cause radial expansion. To keep plasma in its position, the Lorentz force should be applied by vertical magnetic field to balance these forces. Control of the plasma position in the radial direction is very complicated. Poloidal beta, βθ, and the internal inductance parameter depend on plasma current where plasma current parameters themselves are not steady in tokamak. The experimental data of Damavand tokamak is used to compare radial displacement with theoretical prediction. Temporal variation of plasma current along with time variation of R and Z positions of the plasma column is studied. The vertical displacement event takes place because of the elongated cross section of plasma column. Theoretical and experimental results show reasonable agreement.