Simultaneous optical polarimetry and X-ray data of the near synchronous polar RX J2115-5840

We present simultaneous optical polarimetry and X-ray data of the nearsynchronous polar RX J2115-5840. We model the polarisation data using theStokes imaging technique of Potter et al. We find that the data are bestmodelled using a relatively high binary inclination and a small angle betweenthe magnetic and spin axes. We find that for all spin-orbit beat phases, asignificant proportion of the accretion flow is directed onto the lowerhemisphere of the white dwarf, producing negative circular polarisation. Onlyfor a small fraction of the beat cycle is a proportion of the flow directedonto the upper hemisphere. However, the accretion flow never occurs near theupper magnetic pole, whatever the orientation of the magnetic poles. Thisindicates the presence of a non-dipole field with the field strength at theupper pole significantly higher. We find that the brightest parts of the hardX-ray emitting region and the cyclotron region are closely coincident