Effect of the magnetohydrodynamic modes on generation of the nonthermal electrons in high density tokamak plasma

Abstract

Various types of nonthermal x-ray bursts are observed in the central part of plasma with high density in the T-10 tokamak [Alikaev et al., Plasma Phys. Controlled Fusion 30, 381 (1988)] with the use of a tangential view x-ray imaging system. In contrast with the “classical” hard x-ray bursts produced during the interaction of the runaway electron beams (Eγ∼0.5–3 MeV) with the tokamak wall, the “internal” bursts are associated with forward bremsstrahlung emission of the suprathermal electrons (Eγ∼25–100 keV) from the plasma area around the q=1 and q=2 magnetic surfaces. It is speculated that localized beams of the suprathermal electrons can be induced during magnetic reconnection around the X points of the m=1, n=1, and m=2,n=1 magnetic islands. Numerical simulations indicate that generation and losses of the suprathermal electrons in plasma with high density depend critically on the rate of the reconnection and amplitude of the magnetohydrodynamic modes.