Eur. Phys. J. D 26, 275-283 (2003)
https://doi.org/10.1140/epjd/e2003-00258-6

Analysis of the merger between plasma vortices in a Penning trap

Istituto Nazionale per la Fisica della Materia (INFM) and Dipartimento di Energetica, Politecnico di Torino, corso Duca degli Abruzzi 24, 10129 Torino, Italy

Corresponding author: ^a gianni.coppa@polito.it

Received: 18 April 2003
Published online: 12 August 2003

Abstract

In the paper, the interaction between a finite-size vortex of constant density and a weak, pointlike vortex in a Penning trap is studied analytically. A suitable Fourier representation for the contour of the finite vortex is considered and a model for small perturbations, which is linear with respect to the Fourier coefficients, is deduced. The resonance condition for the surface modes and a sufficient condition for the merger of the vortices not to occur are obtained. The validity of the analytic results is checked with a contour dynamics code making use of a new methodology developed by the authors. Numerical results referred to a case of strongly-interacting vortices are also reported.