Searching for spiral shocks
  Spiral shocks in cataclysmic variables (CVs) are the result of tidal interactions of the mass donor star with the accretion disc. Their study is fundamental for our understanding of angular momentum transfer in discs. In our quest to learn how widespread amongst binaries spiral shocks are, and how their presence depends upon orbital period and mass ratio (as they are created by direct interaction with the donor star), we have obtained spectra of a large sample of CVs during their high-mass-transfer states. We find that 24 out of the 63 systems observed are candidates for containing spiral shocks. 5 out of those 24 CVs have been confirmed as showing shocks in the disc during outburst. 
L. Morales-Rueda, T. R. Marsh (University of Southampton)