Analysis of the merger between plasma vortices in a Penning trap G. G.M. Coppa, A. D'Angola, F. Peano and F. Peinetti Eur. Phys. J. D, 26 3 (2003) 275-283 Published online: 12 August 2003 DOI: 10.1140/epjd/e2003-00258-6