Two-dimensional ring-like vortex and multisoliton nonlinear structures at the upper-hybrid resonance

Two-dimensional (2D) equations describing the nonlinear interaction between upper-hybrid and dispersive magnetosonic waves are presented. Nonlocal nonlinearity in the equations results in the possibility of the existence of stable 2D nonlinear structures. A rigorous proof of the absence of collapse in the model is given. Different types of nonlinear localized structures such as fundamental solitons, radially symmetric vortices, nonrotating multisolitons (two-hump solitons, dipoles, and quadrupoles), and rotating multisolitons (azimuthons) have been found numerically. It is shown by direct numerical simulations that 2D fundamental solitons with a negative Hamiltonian are stable.