What is the imprint of the dynamics of solar closed-field structures in the solar wind? – CROSSWIND

With the CROSSWIND project we will aim to estimate the imprint of the dynamics of closed-field structures — that constitute most of the coronal volume in the solar atmosphere — in the young solar wind.
We will in particular focus our effort on studying the interplay between the thermodynamics of the ionized gas and magnetic reconnection in the solar atmosphere. More specifically, we will study the mechanisms of thermal non-equilibrium (TNE) and interchange reconnection (ICR) — magnetic reconnection at boundaries between closed and open field structures. TNE is a thermodynamical state set by a stratified (mainly at the footpoints) and quasi-steady heating. TNE is observed in a majority of coronal loops in active regions and manifests as evaporation-condensation cycles. As such TNE is a key process for the mass and energy transport in the solar atmosphere. Up to now the consequences of this mechanism for the solar wind are unknown.

We will test the hypothesis that TNE is also present at the closed-field sources of the solar wind, at open-closed boundaries. For example, TNE could constrain the ICR process by driving cyclic ICR in pseudo-streamers, at fine-spine topologies (FSTs) and at the edge of active regions (AR) in the so-called « fan loops ». It could also inject mass and energy into the solar wind by its interplay with ICR. Our two main objectives are: (1) to characterize TNE cycle events at the sources of the solar wind and (2) to estimate the solar wind variability driven by TNE cycles.
We will use remote-sensing observations of the solar atmosphere (mainly with SDO and the newest observations of Solar Orbiter) and in situ measurements in the young solar wind (with Parker Solar Probe), combined with new predictions of solar wind observables.
With the CROSSWIND project we will conduct a comprehensive observational study, supported by state-of-the-art numerical simulations of the solar corona and wind.