  Although the basic concept of a stellarator was known since the early days of
fusion research, advances in computational technology have enabled the
modelling of increasingly complicated devices, leading up to the construction
of Wendelstein 7-X, which has recently shown promising results. This recent
success has revived interest in the nonlinear 3D MHD modelling of stellarators
in order to better understand their performance and operational limits. This
paper reports on the extension of the JOREK code to 3D geometries and on the
first stellarator simulations carried out with it. The first simple simulations
shown here address the classic Wendelstein 7-A stellarator using a reduced MHD
model previously derived by us. The results demonstrate that stable full MHD
equilibria are preserved in the reduced model: the flux surfaces do not move
throughout the simulation, and closely match the flux surfaces of the full MHD
equilibrium. Further, both tearing and ballooning modes were simulated, and the
linear growth rates measured in JOREK are in reasonable agreement with the
growth rates from the CASTOR3D linear MHD code.
