Modeling of ion-cyclotron resonant heating in Wendelstein 7-X equilibrium

W7X stellarator 3D equilibrium has been computed with the equilibrium code ANIMEC (Anisotropic Neumann Inverse Moments Equilibrium Code). This equilibrium was used to model ICRH minority heating in 4 He(H) plasma with the 3D full-wave code LEMan (Low frequency ElectroMagnetic wave propagation). The coupled power spatial distribution is shown for different resonance positions within the range of frequencies foreseen for the ICRH antenna. It is found that for the high mirror equilibrium examined, the antenna frequency can be chosen to optimise the power deposition in the plasma core while limiting the absorption at the edge. 1. Introduction Wendelstein 7-X (W7X) is a large superconducting quasi-isodynamic stellarator under construction in Greifswald, Germany. This fully optimised device aims at demonstrating the feasibility of operating steady state plasmas relevant for a fusion powerplant while assuring the confinement of fast particles. Several sources of heating will be mixed in W7X in order to reach fusion plasma relevant temperatures. An assessment of the viability of ion-cyclotron resonance heating (ICRH) applied to W7X constitutes an important step to determine whether this approach is feasible. The design of antennas for this method of heating relies heavily on ICRH simulations in quasi-isodynamic stellarator systems. Numerical simulations using three-dimensional codes were performed to compute a W7X relevant equilibrium and wave propagation in the ICRH range of frequency. A high-mirror equilibrium was produced using the equilibrium code ANIMEC (Anisotropic Neumann Inverse Method Equilibrium Code) [1]. The full-wave code LEMan (Low frequency ElectroMagnetic wave propagation) [2] uses this equilibrium to solve the wave equation to 0th order in Larmor radius including warm contributions to the dielectric tensor. LEMan is therefore limited to the calculation of fundamental minority heating scenarios. According to Ref. [3] in particular one of the antenna designs foreseen for W7X cover a range of frequencies valid for fundamental minority heating of H in D or 4 He, which are scenarios LEMan can compute. However the neutrons generated by D-D fusion reactions may activate the machine which renders deuterium a less desirable majority species for ICRH scenarios for machine maintenance purposes. Consequently we will focus here on 4 He(H) plasmas. This paper is organised as follow. Section 2 describes the main features of the equilibrium case on which the wave propagation is based. In section 3 we discuss the plasma parameters and the scan perfomed in the wave calculation. In section 4 we present the power deposition on the …