Association of intermittency with electron heating in the near-Sun solar wind

Abstract

Several studies in the near-Earth environment show that intermittent structures are important sites of energy dissipation and particle energization. Recent Parker Solar Probe (PSP) data, sampled in the near-Sun environment, have shown that proton heating is concentrated near coherent structures, suggesting local heating of protons by turbulent cascade in this region. However, whether electrons exhibit similar behavior in the near-Sun environment is not clear. Here, we address this question using PSP data collected near the Sun during the first seven orbits. We use the partial variance of increments (PVI) technique to identify coherent structures. We find that electron temperature is preferentially enhanced near strong discontinuities. Our results provide strong support for inhomogeneous heating of electrons in the ‘young’ solar wind, associated with dissipation of turbulent fluctuations near intermittent structures.

The Opposite Behaviors of Proton and Electron Temperatures in Relation to Solar Wind Magnetic Energy: Parker Solar Probe Observations

“…processes in the solar wind, for instance, the electron heat flux, kinetic Alfvén waves, ion acoustic waves, and intermittent structures (Gary et al 1998;Sahraoui et al 2009;Mozer et al 2022;Hubert et al 2023;Phillips et al 2023). The present study tends to imply that some ion-scale process of turbulence may affect the electron temperature since the considerable correlation between T e and P k exists near ion scales.…”

Exploring Turbulence from the Sun to the Local Interstellar Medium

“…Many aspects of how the cascade operates in the kinetic regime are unknown, especially in the outer heliosphere. Debated topics include the preferential ion heating vs the electron heating and temperature anisotropy [18,12,104,117,125]; specific phenomenology dominating in the kinetic regimes; role of turbulence in driving ion beams [122,121] and kinetic microinstabilities [16]; role of ICWs [8], and PUI-driven instabilities [52,112].…”

Exploring turbulence from the Sun to the local interstellar medium: Current challenges and perspectives for future space missions

“…Many aspects of how the cascade operates in the kinetic regime are unknown, especially in the outer heliosphere. Debated topics include the preferential ion heating vs. the electron heating and temperature anisotropy (Breech et al, 2009;Boldyrev et al, 2020;Phillips et al, 2022;Sioulas et al, 2022;Squire et al, 2022); specific phenomenology dominating in the kinetic regimes; role of turbulence in driving ion beams (Sorriso-Valvo et al, 2019a, Sorriso-Valvo et al, 2019b and kinetic microinstabilities (Bowen et al, 2020); role of ICWs (Bale et al, 2019), and PUI-driven instabilities (Florinski et al, 2016;Roytershteyn et al, 2019).…”