  Observation of solar-like stars show a clear relation between X-ray emission
and their rotation. Higher stellar rotation can lead to a larger magnetic
helicity production in stars. We aim to understand the relation between
magnetic helicity on the surface of a star to their coronal X-ray emission. We
use 3D MHD simulations to model the corona of the solar-like stars. We take an
observed magnetogram as in photospheric activity input, and inject different
values of magnetic helicity. We use synthesis emission to calculate the X-ray
emission flux of each simulation and investigate how this scales with injected
magnetic helicity. We find that for larger injected magnetic helicities an
increase in temperature and an increase in X-ray emission. The X-ray emission
scaled cubicly with the injected helicity. We can related this to increase of
horizontal magnetic field and therefore higher Poynting flux at the coronal
base. Using typical scaling of magnetic helicity production with stellar
rotation, we can explain the increase of X-ray emission with rotation only by
an increase of magnetic helicity at the surface of a star.
