Simultaneous Attainment of High Electron and Ion Temperatures in Discharges with Internal Transport Barriers in ASDEX Upgrade

S. Günter; R. C. Wolf; F. Leuterer; O. Gruber; M. Kaufmann; K. Lackner; M. Maraschek; P. J. Mc Carthy; H. Meister; A. Peeters; G. Pereverzev; H. Salzmann; S. Schade; J. Schweinzer; W. Suttrop; the ASDEX Upgrade Team

doi:10.1103/PhysRevLett.84.3097

Simultaneous Attainment of High Electron and Ion Temperatures in Discharges with Internal Transport Barriers in ASDEX Upgrade

S. Günter, R. C. Wolf, F. Leuterer, O. Gruber, M. Kaufmann, K. Lackner, M. Maraschek, P. J. Mc Carthy, H. Meister, A. Peeters, G. Pereverzev, H. Salzmann, S. Schade, J. Schweinzer, W. Suttrop, and the ASDEX Upgrade Team

Phys. Rev. Lett. 84, 3097 – Published 3 April 2000

Abstract

Internal transport barriers have been demonstrated to exist also under conditions with $T_{e} \approx T_{i} \approx 10 keV$ and predominant electron heating of the tokamak core region. Central electron cyclotron heating was added to neutral beam injection–heated 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.