Section: New Results

Gyroaverage operator on polar mesh

In [36] , in collaboration with C. Steiner, M. Mehrenberger (University of Strasbourg) V. Grandgirard, G. Latu (IRFM, Cadarache). In this work, we are concerned with numerical approximation of the gyroaverage operators arising in plasma physics to take into account the effects of the finite Larmor radius corrections. The work initiated in [Crouseilles, Mehrenberger, Sellama, CiCP 2010] is extended here to polar geometries. A direct method is proposed in the space configuration which consists in integrating on the gyrocircles using interpolation operator (Hermite or cubic splines). Numerical comparisons with a standard method based on a Pade approximation are performed: (i) with analytical solutions, (ii) considering the 4D drift-kinetic model with one Larmor radius and (iii) on the classical linear DIII-D benchmark case [6]. In particular, we show that in the context of a drift-kinetic simulation, the proposed method has similar computational cost as the standard method and its precision is independent of the radius.