Magnetic reconnection at the Sun and in the heliosphere: Theories, observations, and evolution of views

Magnetic reconnection is known to transform the magnetic energy into other forms of energy in laboratory and space plasmas. Solar physics and physics of the terrestrial magnetosphere consider this mechanism as the main candidate for acceleration of charged particles to suprathermal energies at reconnecting current sheets. It took scientists several decades to make the way from imaging magnetic reconnection as the simplest Petschek or Sweet-Parker mechanism operating at Harris-type current sheets to understanding this as a 3D turbulent/intermittent/stochastic process associated with creation of flux ropes, secondary current sheets and waves. Studies of magnetic reconnection in the solar wind were far less easy than those in the magnetosphere, first of all, because of the insufficiency of data from spacecraft and the absence of multi-point observations in the heliosphere. As a result, the views on the subject developed in the same way as in magnetospheric physics but it took us longer to realize some critical points about the complexity of magnetic reconnection in heliospheric plasmas. Furthermore, the idea of local particle acceleration by magnetic reconnection in the solar wind has been denied for a long time, and the situation shifted toward its acceptance only during the last decade. Historical and modern views on magnetic reconnection and local particle acceleration in the heliosphere will be discussed in the presentation, with a focus on observations from past and recent heliospheric missions at different distances from the Sun.

Dr. Khabarova is a candidate for a position in the department