Energy dissipation processes in solar wind turbulence

TL;DR

This paper investigates how energy is dissipated in the nearly collisionless solar wind, focusing on the roles of magnetic reconnection and wave-particle interactions, and provides observational evidence for multifractal dissipation near reconnection sites.

Contribution

It presents the first observational evidence of multifractal dissipation scaling around magnetic reconnection regions in the solar wind.

Findings

Reconnection regions exhibit multifractal dissipation scaling.

Ambient solar wind turbulence shows monofractal dissipation.

Results have implications for understanding fundamental energy dissipation processes.

Abstract

Turbulence is a chaotic flow regime filled by irregular flows. The dissipation of turbulence is a fundamental problem in the realm of physics. Theoretically, dissipation cannot be ultimately achieved without collisions, and so how turbulent kinetic energy is dissipated in the nearly collisionless solar wind is a challenging problem. Wave particle interactions and magnetic reconnection are two possible dissipation mechanisms, but which mechanism dominates is still a controversial topic. Here we analyze the dissipation region scaling around a solar wind magnetic reconnection region. We find that the magnetic reconnection region shows a unique multifractal scaling in the dissipation range, while the ambient solar wind turbulence reveals a monofractal dissipation process for most of the time. These results provide the first observational evidences for the intermittent multifractal dissipation region scaling around a magnetic reconnection site, and they also have significant implications for the fundamental energy dissipation process.