Eur. Phys. J. D (2015) 69: 18
https://doi.org/10.1140/epjd/e2014-50211-7

Regular Article

Gyroaverage operator for a polar mesh^*

¹ IRMA, Université de Strasbourg, 67000 Strasbourg, France
² Max-Planck-Institut für Plasmaphysik, 85748 Garching, Germany
³ Inria-Rennes Bretagne Atlantique, IPSO team et IRMAR, Université de Rennes 1, 35000 Rennes, France
⁴ CEA/DSM/IRFM, Association Euratom-CEA Cadarache, 13108 Saint-Paul-lez-Durance, France
⁵ Maison de la simulation, CEA Saclay, 91191 Gif sur Yvette, France

^a e-mail: mehrenbe@math.unistra.fr

Received: 15 March 2014
Received in final form: 1 August 2014
Published online: 16 January 2015

Abstract

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 reference [N. Crouseilles, M. Mehrenberger, H. Sellama, CiCP 8, 484 (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 Padé 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 [A. Dimits et al., Phys. Plasmas 7, 969 (2000)]. 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.