Multi-line Doppler imaging of MR Ser in high-state
  Doppler images in Balmer, HeI, HeII and CII lines, and simultaneous I-band photometry of the polar MR Ser are presented and analyzed. The Balmer and Helium Doppler tomograms of this bright polar at high mass transfer state show the emission from the accretion flow and the heated surface of the companion star. As a result of a comparison between the Doppler tomograms the ionization structure of the flow could be constrained. The highest ionization region was found in the vicinity of the magnetospheric radius. Photoionization modeling of the accretion column indicates that the Balmer and Helium emission line production in this system can be explained by the central soft Xray illumination only. The orbital ephemeris of MR Ser has been revised. 
Marcos Diaz and Deonisio Cieslinski