April 27, 1:00 pm - 2:00 pm

The reconnection electric field and dissipation in collisionless magnetic reconnection

Michael Hesse (University of Bergen)

It is well-known that magnetic reconnection involves an electric field, which facilitates the transfer of magnetic flux from two inflow regions to the two outflow regions. While this simple role is quite obvious, the physical background behind the existence of this electric field is just beginning to emerge. Investigations based on the Magnetospheric Multiscale mission and concurrent theory and modeling have been exceptionally fruitful in illuminating this problem. Because of very small spatial scales and short time scales, understanding the electron physics at the very center of magnetic reconnection, the ?electron diffusion region (EDR),? has been most challenging. This presentation will begin with an introduction of the basic physical concepts underlying the EDR. We will then proceed to review both theory and models, and MMS observations to form a picture of our present understanding of the structure and dynamics of the critical region. We will then proceed to interpret the role of the electron diffusion region in the greater context of energy conversion and discuss one possible contribution to this conversion on larger scales. We will conclude with a discussion of reversibility in the context of collisionless magnetic reconnection.