Gyrokinetic simulations in stellarators using different computational domains

In this work, we compare gyrokinetic simulations in stellarators using different computational domains, namely, flux tube, full-flux-surface, and radially global domains. Two problems are studied: the linear relaxation of zonal flows stability ion temperature gradient (ITG) modes. Simulations carried out with codes EUTERPE, GENE, GENE-3D, stella magnetic configurations LHD W7-X adiabatic electrons. The flow properties obtained tubes found to differ each other result, except for sufficiently long tubes, general. tube length required convergence is configuration-dependent. Similarly, ITG instabilities, provide results, but discrepancy between them diminishes increasing length. Full-flux-surface show good agreement calculation growth rate frequency most unstable modes LHD, while differences rates full-flux-surface Radially results close ones. radial scale studied finding that W7-X, depends on binormal wavenumber, no clear dependency found.