Analysis of the potential of ICRF waves to heat bulk ions in DEMO D. Gallart 1 , M.J. Mantsinen 1,2 , Y. Kazakov 3 1 Barcelona Supercomputing Center, Barcelona, Spain 2 Catalan Institution for Research and Advanced Studies, Barcelona, Spain 3 Laboratory for Plasma Physics, LPP-ERM/KMS, Brussels, Belgium Introduction Among the auxiliary heating schemes presently envisaged for ITER, heating with waves in the ion cyclotron range of frequencies (ICRF) is the only scheme that can provide dominant bulk ion heating. Ion heating with ICRF waves results from the absorption of the wave power P ICRF by resonant ions P i which can subsequently transfer their energy to the fuel ions via collisions (Fig. 1). This effect is in competition with direct electron damping P e and other mechanisms which can also damp the wave power. Bulk ion heating dominates provided Figure 1: Scheme of the power deposition in the ICRF heating process. that the energy of the resonant ions E ave is tailored to remain below the critical energy E crit at which they transfer energy equally to electrons P ce and ions P ci in collisions. Fast ions transfer their energy via collisions to bulk ions and electrons on the time scale of the slowing-down times on ions τ i−i and electrons τ i−e . For fast 3 He ions and tritons, which will be the main ICRF-resonant ion species in ITER, τ i−i is 1 ms and 3 ms and τ i−e = 1s and 3.4 s, respectively, at typical steady-state ITER parameters. The bulk ion heating capabilities of ICRF waves in ITER have been studied e.g. in Refs. [1, 2]. We analyze the potential of ICRF waves to heat the fuel D-T ions in DEMO. DEMO is a proposed nuclear fusion demonstration power plant that is expected to be built after ITER. While ITER’s main purpose is to confirm the feasibility of nuclear fusion as an energy source, DEMO is planned as the first fusion reactor to produce net electrical energy. Our analysis is carried out for the DEMO 2015 (from now on DEMO2), using the ICRF modelling codes PION [3] and TORIC [4]. We also have analyzed the previous design DEMO 2013 (from now on DEMO1) see Ref. [5]. Analysis of bulk ion heating in DEMO We concentrate our studies on the second harmonic ICRF heating of tritium with and without 3 He in a 50%:50% D-T plasma in DEMO. The ICRF scenario is for a standard low-field side (LFS) midplane launch with thermal plasma (there is 42 nd EPS Conference on Plasma Physics P4.109