Finite Larmor radius approximation for collisional magnetic confinement. Part I: The linear Boltzmann equation

International audienceThe subject matter of this paper concerns the derivation of the finite Lar-mor radius approximation, when collisions are taken into account. Several studies are performed, corresponding to different collision kernels : the relaxation and the Fokker-Planck operators. Gyroaveraging the relaxation operator leads to a position-velocity integral operator, whereas gyroaveraging the linear Fokker-Planck operator leads to diffusion in velocity but also with respect to the perpendicular position coordinates