MAGNETIC RECONNECTION AND PARTICLE ACCELERATION IN THE SOLAR WIND

Magnetic reconnection is known to transform magnetic energy into other forms of energy in laboratory and space plasmas. Solar physics and physics of magnetosphere consider this mechanism as the main candidate for acceleration of charged particles to suprathermal energies at reconnecting current sheets. Meanwhile, the solar wind has been treated as a much simpler medium for a long time, and significant energization of particles has been thought to be impossible there because of too slow inflow speeds. Energetic particles observed at the Earth's orbit have been supposed to come either from the Sun or from shocks. 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 it as a 3D turbulent/intermittent/stochastic process associated with far more effective particle acceleration and creation of flux ropes, secondary current sheets and waves in the solar wind. 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