The Role of Turbulence in Coronal Heating and Solar Wind Expansion

TL;DR

This paper reviews current understanding of coronal heating and solar wind acceleration, emphasizing recent turbulence models and observational data, and discusses unresolved questions about the dominant heating mechanisms in the Sun's corona.

Contribution

It provides a comprehensive overview of turbulence-based models and observational insights into coronal heating and solar wind acceleration, highlighting areas needing further research.

Findings

Recent models successfully predict many properties of the solar wind.

Uncertainty remains whether turbulence dissipation or magnetic reconnection dominates heating.

Ultraviolet spectroscopy offers key observational constraints.

Abstract

Plasma in the Sun's hot corona expands into the heliosphere as a supersonic and highly magnetized solar wind. This paper provides an overview of our current understanding of how the corona is heated and how the solar wind is accelerated. Recent models of magnetohydrodynamic turbulence have progressed to the point of successfully predicting many observed properties of this complex, multi-scale system. However, it is not clear whether the heating in open-field regions comes mainly from the dissipation of turbulent fluctuations that are launched from the solar surface, or whether the chaotic "magnetic carpet" in the low corona energizes the system via magnetic reconnection. To help pin down the physics, we also review some key observational results from ultraviolet spectroscopy of the collisionless outer corona.