EVIDENCE FOR INHOMOGENEOUS HEATING IN THE SOLAR WIND

TLDR

Solar wind observations and MHD simulations probe turbulence heating, and coherent current sheets may serve as sites of magnetic reconnection. The study aims to investigate the kinetic mechanisms that heat and accelerate particles within these structures. Using ACE and Wind data, the authors measured electron heat flux, electron and ion temperatures, and compared these diagnostics with MHD simulation estimates of local dissipation density. Coherent structures are linked to enhancements in all heating diagnostics, supporting the hypothesis that significant inhomogeneous heating occurs in the solar wind through dynamically generated current sheets.

Abstract

Solar wind observations and magnetohydrodynamic (MHD) simulations are used to probe the nature of turbulence heating. In particular, the electron heat flux, electron temperature, and ion temperature in the solar wind are studied using ACE and Wind data. These heating diagnostics are also compared with MHD simulation estimates of the local dissipation density. Coherent structures, which are sources of inhomogeneity and intermittency in MHD turbulence, are found to be associated with enhancements in every heating-related diagnostic. This supports the hypothesis that significant inhomogeneous heating occurs in the solar wind, connected with current sheets that are dynamically generated by MHD turbulence. Indeed, a subset of these coherent current sheets might be candidates for magnetic reconnection. However, the specific kinetic mechanisms that heat and accelerate particles within these structures require further study.