Generating sub-TeV quasi-monoenergetic proton beam by an   ultra-relativistically intense laser in the snowplow regime
  Snowplow ion acceleration is presented, using an ultra-relativistically intense laser pulse irradi- ating on a combination target, where the relativistic proton beam generated by radiation pressure acceleration can be trapped and accelerated by the laser plasma wakefield. The theory suggests that sub-TeV quasi-monoenergetic proton bunches can be generated by a centimeter-scale laser wakefield accelerator, driven by a circularly polarized (CP) laser pulse with the peak intensity of 10^23W/cm^2 and duration of 116fs. 
F.L.Zheng, H.Y.Wang, X.Q.Yan, J.E.Chen, Y.R.Lu, Z.Y.Guo, T.Tajima, and   X.T.He
physics.plasm-ph