ICRH in radiatively cooled TEXTOR-94 plasmas

To reach the recently established Radiative Improved Mode (RI-Mode) with full performance the additional heating power must include at least a small fraction of neutral beam co-injection. The role of ICRH is essential because it allows to perform this regime in quasi-stationary conditions by maintaining a constant β value using feedback control of the ICRH power level. The confinement properties and the performance achieved have been analysed varying the ratio of neutral beam co-injection over the ICRH power. It is shown that above a threshold density confinement increases with density in all cases (as for the ohmic Neo-Alcator scaling), in contrast to the usual L and H mode scalings. The deterioration of confinement with total applied power remains. The RI-Mode regime has been established on TEXTOR-94 with Ne or Ar seeding.