Small-scale Current Sheets and Magnetic Reconnection in the Turbulent Solar Wind

Magnetic reconnection is an energy dissipating process, in which magnetic field topology is modified, eroding the magnetic field, and turning the magnetic energy into thermal and kinetic energy of the plasma. Magnetic reconnection has been observed through a wide range of scales in the solar system, from thousands of ion inertial lengths in the heliospheric current sheet to few electron inertial lengths in Earth’s magnetosheath. However, the smaller scales were not accessible in the solar wind until the launch of Solar Orbiter and Parker Solar Probe, and therefore ion-scale magnetic reconnection had not been studied in the solar wind.

 

Non-linear interactions drive turbulence in the solar wind, transferring energy across scales at a constant rate, seen as a constant slope in the energy spectrum of magnetic fluctuations. However, a spectral break is observed at scales close to and below the ion inertial length. It has been proposed that the magnetic energy dissipated through magnetic reconnection at scales of the ion inertial length or smaller can account in part for this break in the magnetic fluctuation energy spectrum.

 

In the present work, we have harnessed the high cadence of the Solar Orbiter in-situ instrumentation (Solar Wind Analyzer and Magnetometer) to search for magnetic reconnection at scales in the order of few to tens ion inertial lengths. We compiled a catalog of 979 thin current sheets, 5% of which undergo reconnection. Statistics of CS properties and Solar Wind conditions around these has been performed, with a double aim: assessing the relation between turbulence and reconnection; and evaluate the influence of different Solar Wind parameters on ion-scale reconnection.