ELECTRON-CYCLOTRON-RESONANCE HEATING EXPERIMENTS IN THE GAMMA-10 TANDEM MIRROR

Two aspects of ECRH experiments in the GAMMA 10 tandem mirror are desc ribed. One is hot electron production in a minimum-B anchor cell by se cond harmonic ECRH. When a resonance region is located at the centre o f the anchor cell, hot electrons are piled up near the centre region a nd the beta-value attains more than 20%. For off-centre resonance, hot electrons have a spatial profile like a baseball seam. This profile i s explained by a drift orbit of an electron in a minimum-B field. The other topic is observation of an intense axial electron flow with ener gy from hundreds of eV to a few keV generated by fundamental ECRH in t he end cells. The force due to the fundamental ECRH driving heated ele ctrons into the mirror loss cone is particularly strong. A bounce aver aged Fokker-Planck code with a quasi-linear diffusion operator reprodu ces the electron flow with the same energies. The electron flow is a p redominant ingredient for generation of the electrostatic potential in the GAMMA 10.