Current driven rotating kink mode in a plasma column with a   non-line-tied free end
  First experimental measurements are presented for the kink instability in a linear plasma column which is insulated from an axial boundary by finite sheath resistivity. Instability threshold below the classical Kruskal-Shafranov threshold, axially asymmetric mode structure and rotation are observed. These are accurately reproduced by a recent kink theory, which includes axial plasma flow and one end of the plasma column that is free to move due to a non-line-tied boundary condition. 
I. Furno, T.P. Intrator, S. Abbate, T. Madziwa-Nussinov, A. Light, L.   Dorf, G. Lapenta (Los Alamos National Laboratory), D...