P2.13 Hybrid MHD-Gyrokinetic codes: extended models, new implementations and forthcoming applications G. Vlad, S. Briguglio, G. Fogaccia, F. Zonca Associazione EURATOM-ENEA, CR ENEA-Frascati, Via E. Fermi 45, 00044 Frascati, (Rome) Italy e-mail contact of main author: gregorio.vlad@enea.it Abstract. The hybrid MHD-Gyrokinetic model has been proven to be very successful in describing the coupling between Alfv´ en waves and energetic particles and their mutual interaction in toroidal devices. HMGC, the nonlin- ear MHD-Gyrokinetic code originally developed at the Frascati laboratories, is being currently extended to include new physics. In this paper we will present the first simulations of an electron fishbone mode using the extended HMGC code. We will also present some benchmarks of the new hybrid code HYMAGYC (linear resistive MHD in general curvilinear geometry plus fully nonlinear gyrokinetic description, k ⊥ ρ H ∼ 1, of the energetic particles) with the results obtained by HMGC and an analytical expression of the energetic particle response. 1. Introduction The hybrid MHD-Gyrokinetic model [1] has been proven to be very successful in describ- ing the coupling between Alfv´ en waves and energetic particles and their mutual interaction in toroidal devices [2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. HMGC [2], the nonlinear MHD-Gyrokinetic code originally developed at the Frascati laboratories, has been applied to case studies of en- ergetic particle driven modes (such as, e.g., TAEs and EPMs [3, 4, 5]), but also to analyses of experimentally observed modes in existing devices (JT-60U [12], DIII-D [13]) and forth- coming (ITER [6, 14]) or proposed (FAST [15]) burning plasmas experiments. The simple physical model, originally used in HMGC (O(ǫ 3 ) nonlinear reduced MHD equations, circular shifted magnetic surface equilibrium, zero bulk plasma pressure, and drift-kinetic fast ions), has been recently extended to include new physics, which are currently under implementation and/or benchmarking [16]. These extensions include both thermal ion compressibility and dia- magnetic effects, in order to account for thermal ion collisionless response to low-frequency Alfv´ enic modes driven by energetic particles (e.g., KBAEs), and finite parallel electric field due to parallel thermal electron pressure gradient, which enters the parallel Ohm’s law and generalizes it, accounting for the kinetic thermal plasma response. Moreover, HMGC is now able to treat two independent particle populations kinetically, assuming different equilibrium distribution functions (as, e.g., bulk ions, energetic particles accelerated by NB, IRCH, fusion generated alpha particles, etc.). Applications of the extended HMGC include, e.g., kinetic ther- mal ion effects on Alfv´ enic fluctuations, electron and ion fishbones, KBAEs, fast ion driven GAMs, EPMs in burning plasma experiments with multiple fast ion species (as in the case of FAST [15]). The HMGC code also participates to several benchmark activities within the ITPA Energetic Particle group [17] and the SciDAC GSEP collaboration [18]. On a separate ground, the new hybrid code HYMAGYC [19] (linear resistive MHD in general curvilinear geometry plus fully nonlinear gyrokinetic description, k ⊥ ρ H ∼ 1, of the energetic particles) is under test- ing: several benchmarks between HYMAGYC and HMGC in overlapping regimes of validity and comparison with analytically computed particle responses are underway. In the following sections, the first results obtained in simulating an electron fishbone mode using the extended HMGC code (see Sect. 2), and a detailed benchmark of the gyrokinetic model of HYMAGYC both with analytical expressions and HMGC results for the particles responses (see Sect. 3) will be presented.