  The magnetized wind from stars that impact exoplanets should lead to radio
emissions. According to the scaling laws derived in the solar system, the radio
emission should depend on the stellar wind, interplanetary magnetic field, and
topology of the exoplanet magnetosphere. The aim of this study is to calculate
the dissipated power and subsequent radio emission from exoplanet
magnetospheres with different topologies perturbed by the interplanetary
magnetic field and stellar wind, to refine the predictions from scaling laws,
and to prepare the interpretation of future radio detections. We use the
magnetohydrodynamic (MHD) code PLUTO in spherical coordinates to analyze the
total radio emission level resulting from the dissipation of the kinetic and
magnetic (Poynting flux) energies inside the exoplanet's magnetospheres. We
apply a formalism to infer the detailed contribution in the exoplanet radio
emission on the exoplanet's day side and magnetotail. The model is based on
Mercury-like conditions, although the study results are extrapolated to
exoplanets with stronger magnetic fields, providing the lower bound of the
radio emission. The predicted dissipated powers and resulting radio emissions
depends critically on the exoplanet magnetosphere topology and interplanetary
magnetic field (IMF) orientation. The radio emission on the exoplanet's night
and day sides should thus contain information on the exoplanet magnetic field
topology. In addition, if the topology of an exoplanet magnetosphere is known,
the radio emission measurements can be used as a proxy of the instantaneous
dynamic pressure of the stellar wind, IMF orientation, and intensity.
