Fast magnetic reconnection and particle acceleration in the non-equilibrium magnetosphere of a relativistic star

A scenario for hard impulsive flares due to magnetic reconnection and particle acceleration in cosmic plasma is proposed. The properties of fast reconnection in an appreciably non-equilibrium nagnetosphere of a compact relativistic object, such as a neutron star, magnetar, or white dwarf, are discussed. Such a magnetosphere could form as the result of the action of a relativistic shock on the strong magnetic field of the star. An analytical solution is presented for the generalized, two-dimensional structure, shape, and boundaries of the magnetosphere, together with the magnitudes of the direct and reverse currents in the reconnecting current layer. The uncompensated magnetic force acting on the reverse current is determined. The characteristic parameters of the non-equilibrium magnetospheres of compact stellar objects are estimated. The excess magnetic energy of the magnetosphere is comparable to the mechanical energy carried by the shock at the time of impact. The possible acceleration of particles to gigantic energies is discussed.