Beam Ion–Driven Alfvén Instabilities in T-15 Baseline Scenario

Properties of toroidal Alfvén eigenmodes (TAEs), driven by neutral beam injection (NBI) hot ions, are described for the tokamak T-15 under construction in the Kurchatov Institute to test a possible influence on the beam and plasma particle losses. The T-15 baseline scenario with a 10-s flat-top 2 MA current stage, 6-MW NBI plus 6 MW of electron cyclotron resonance (ECR) heating is computed with the ASTRA code. The spatial structure and the frequencies of different TAE modes with the toroidal indexes n = 2 to 8 have been obtained with the ideal magnetohydrodynamic KINX code. The bulk plasma Landau damping, linear growth rates, and nonlinear evolution of the TAE mode amplitudes driven by the NBI ions have been computed with the VENUS code. Our numerical estimations for the T-15 TAE modes are compared with experimental and theoretical results for the DIII-D and NSTX tokamaks.