Cluster coulomb explosion in a hot plasma interface

We investigate the deformations of a planar corona of point-like charged particles impacting on a dense electron plasma. We establish a simple criterion of non-deformation of the cluster that relies on the ratios between the initial size of the corona and the thickness of the plasma-vacuum interface, and that between the internal Coulomb and kinetic initial energies of the corona, through a competition between Coulomb explosion and the plasma sheath deformation of the impinging cluster.