Simultaneous attainment of high electron and ion temperatures in discharges with internal transport barriers in ASDEX upgrade

Internal transport barriers have been demonstrated to exist also under conditions with T-c approximate to T-i approximate to keV and predominant electron heating of the tokamak core region. Central electron cyclotron heating was added to neutral beam injection-healed ASDEX Upgrade discharges with a preexisting internal transport barrier, established through programmed current ramping leading to shear reversal. Compared to a reference internal transport barrier discharge without electron cyclotron resonance heating, the electron heat conductivity in the barrier region was found not to increase, in spite of a fivefold increase in electron heat flux, and also angular momentum and ion energy transport did not deteriorate.