The spectrum of ion cyclotron emission from neutral beam injection heated plasma on the TUMAN-3M tokamak

Radiation at the ion cyclotron resonance frequencies in both the ohmic mode and the injection heating mode–ion cyclotron emission (ICE)–is observed on the TUMAN-3M tokamak (minor radius $a$ = 0.25 m, major radius $R_0$ = 0.5 m, toroidal field $B_T$ = 1 T, plasma current $I_p\le$ 180 kA, and average plasma electron density $n_e\le$ 5 $\times$ 10$^{19}$ m$^{-3}$). Usually, the ICE is associated with the presence of high-energy ions in the plasma. Such ions may be products of a thermonuclear reaction or arise as a result of additional plasma heating, e.g., by means of electromagnetic waves or by injection of beams of high-energy atoms (neutral beam injection, NBI). The properties of the ICE in the TUMAN-3M tokamak in the NBI-heating mode and their possible connection with the features of fast ion trajectories and their energy spectrum are considered.