GENE-3D: A global gyrokinetic turbulence code for stellarators

•Development and verification of gyrokinetic plasma turbulence code GENE-3D.•GENE-3D is able to consider plasma turbulence in three-dimensional magnetic equilibria.•First code to consider multiple gyrokinetic species (incl. electrons) in a 3D geometry.•GENE-3D is massively parallelized suitable for present day supercomputers.•First turbulence simulation results of the Wendelstein 7-X stellarator are presented. A detailed description of GENE-3D, a newly developed global stellarator version of the well established gyrokinetic turbulence code GENE, is provided – along with some initial simulation results. First, the underlying gyrokinetic equations and the use of field-aligned coordinates in non-axisymmetric magnetohydrodynamic equilibria are discussed. Then, various aspects regarding the numerical implementation in GENE-3D are described. Finally, the code is validated and its parallel performance is assessed, along with the influence of numerical precision.