Turbulent Coronal Heating Mechanisms: Coupling of Dynamics and Thermodynamics

Abstract

Context. Photospheric motions shuffle the footpoints of the strong axial magnetic field that threads coronal loops giving rise to turbulent nonlinear dynamics characterized by the continuous formation and dissipation of field-aligned current sheets where energy is deposited at small-scales and the heating occurs. Previous studies show that current sheets thickness is orders of magnitude smaller than current state of the art observational resolution (~700 km). Aim. In order to understand coronal heating and interpret correctly observations it is crucial to study the thermodynamics of such a system where energy is deposited at unresolved small-scales. Methods. Fully compressible three-dimensional magnetohydrodynamic simulations are carried out to understand the thermodynamics of coronal heating in the magnetically confined solar corona. Results. We show that temperature is highly structured at scales below observational resolution and nonhomogeneously distributed so that only a fraction of the coronal mass and volume gets heated at each time. Conclusions. This is a multi-thermal system where hotter and cooler plasma strands are found one next to the other also at sub-resolution scales and exhibit a temporal dynamics.

A&A Letter, in press

References in corpus (2)

• Coronal Heating, Weak MHD Turbulence and Scaling Laws
• Diamagnetic and Expansion Effects on the Observable Properties of the Slow Solar Wind in a Coronal Streamer

Cited by in corpus (8)

• Coronal heating by MHD waves
• The First Ionization Potential Effect from the Ponderomotive Force: On the Polarization and Coronal Origin of the Alfven Waves
• Energy Dissipation in Magnetohydrodynamic Turbulence: Coherent Structures or "Nanoflares"?
• Ponderomotive Acceleration in Coronal Loops
• Structures in the outer solar atmosphere
• Coronal Heating Topology: the Interplay of Current Sheets and Magnetic Field Lines
• Energetics and 3-D Structure of Elementary Events in Solar Coronal Heating
• Explaining Inverted Temperature Loops in the Quiet Solar Corona with Magnetohydrodynamic Wave Mode Conversion