A general hybrid kinetic-fluid model for collisionless magnetic reconnection

A general set of equations appropriate for the description of the plasma dynamics within a collisionless magnetized plasma during the process of magnetic reconnection is derived. The particular geometry considered is that of a Harris pinch with a guide field and full kinetic equations for the perturbations are found, valid within the singular layer around the reconnecting region. Ion equations take into account finite Larmor radius effects while electron dynamics is based on the gyro-averaged drift kinetic equation. A more manageable model is obtained by resorting to fluid equations for the ions and retaining electron kinetic effects. It is shown that these equations give the same results obtained from the two-fluid theory in the limit of the collisionless tearing mode for different regimes.