Rigid rotor equilibria with non-neutral plasma: analytical relativistic two fluid model Filipe L. Braga, Diego N. Soares and Weslley A. Lourenço Eur. Phys. J. D, 70 7 (2016) 150 Published online: 12 July 2016 DOI: 10.1140/epjd/e2016-60588-8