Description of the Objective


Reconnection is a universal plasma process that occurs in coronal, magnetospheric, astrophysical, and lab plasmas. Reconnection exhausts have also been observed in the solar wind (Gosling & Phan, 2013; Enzl et al., 2014; Mistry et al., 2017). This mechanism transfers energy from the magnetic field to the particles in the form of acceleration and heating. However, the role of reconnection as a dissipation mechanism in the turbulent solar wind is not yet understood. Although there are magnetospheric missions (like MMS) with a dedicated focus on reconnection, we have not quantified the importance of local reconnection for the global evolution of the solar wind. Using Solar Orbiter to compare local solar-wind measurements with magnetospheric multi-spacecraft measurements of reconnection can help us to understand the ion and electron physics in and near current sheets with thickness down to the ion scales and smaller.

Needed Observations

Reconnection is characterised by a restructuring of the magnetic field and certain characteristic plasma flow patterns. Combining fields and particle measurements, we will use SWA and MAG data to resolve these features on small scales corresponding to the ion inertial length and below. We will determine the statistical occurrence rate of current sheets as large gradients in the magnetic field and then combine this measurement with studies of the convected flow patterns around the current sheets. In this way, we will estimate the occurrence of ongoing reconnection in the solar wind and its importance for the thermalisation of the plasma. The unique high-resolution particle instruments will allow us to study the reconnection physics down to scales smaller than the ion scales, where the physics of collisionless reconnection is believed to occur and modify the distribution function of the plasma (Egedal et al., 2012).

YZ: Link to Reconnection