Dynamics of non-stationary dipole vortices in the Hasegawa-Mima equation

The dynamics of tilted dipole vortices in the Hasegawa-Mima equation is studied. A recent theory is compared with numerical simulations and found to describe the short time behaviour of dipole vortices well. In the long time limit the dipoles are found to either disintegrate or relax toward a steady dipole vortex counter propagating relative to the linear drift waves. This relaxation is a consequence of nonviscous enstrophy loss by the dipole vortex. (author) 4 refs., 2 figs