Results of experiments on ICR-heating of hot initial plasma at the end system of AMBAL-M are reported. The heating is performed by an antenna of “Nagoya-III” type installed in the transition region between the mirror and the semicusp. Varying the magnetic field strength in the mirror it was found that the plasma heating in the mirror occurred both at the first and at the second frequency harmonics. The heating does not result in any detectable distortion of the azimuthal symmetry of the initial plasma. The experiments with a small radius of the initial plasma allowed to determine coefficient of diffusion arising in result of RF heating. Measurements of the RF fields spectrum in the plasma demonstrated the emergence of the second frequency harmonic.

At the limiting ICR-heating power it was found that after the pulse of the initial plasma created by the gas-discharge source, the steady-state plasma with duration of 40 ms was sustained in the mirror during RF-power input. The steady state plasma is fed by hydrogen puffing arising in result of considerable recycling. The steady state plasma has the density ∼1012 cm−3, electron temperature ∼40 eV, ion energy 300–400 eV.