Wake-induced bending of two-dimensional plasma crystals
  It is shown that the wake-mediated interactions between microparticles in a two-dimensional plasma crystal affect the shape of the monolayer, making it non-flat. The equilibrium shape is calculated for various distributions of the particle number density in the monolayer. For typical experimental conditions, the levitation height of particles in the center of the crystal can be noticeably smaller than at the periphery. It is suggested that the effect of wake-induced bending can be utilized in experiments, to deduce important characteristics of the interparticle interaction. 
T.B. R\"ocker, A.V. Ivlev, S.K. Zhdanov, L. Cou\"edel, and G.E.   Morfill
physics.plasm-ph