Temperature inversion in a gravitationally bound plasma: Case of the solar corona

Abstract

The temperature of the solar atmosphere increases from thousands to millions of degrees moving from the lower layer (chromosphere) to the outermost one (corona), while the density drops accordingly. The mechanism behind this phenomenon, known as a temperature inversion, is still unknown. In this work, we model a coronal loop as a collisionless plasma confined in a semicircular tube that is subject to the Sun's gravity and in thermal contact with a fully collisional chromosphere behaving as a thermostat at the loop's feet. By using kinetic $N$-particle simulations and analytical calculations, we show that rapid, intermittent, and short-lived heating events in the chromosphere drive the coronal plasma towards a non-equilibrium stationary state. The latter is characterized by suprathermal tails in the particles' velocity distribution functions, exhibiting temperature and density profiles strikingly similar to those observed in the atmosphere of the Sun. These results suggest that a million-Kelvin solar corona can be produced without the local deposition of heat in the upper layer of the atmosphere that is typically assumed by standard approaches. We find that suprathermal distribution functions in the corona are self-consistently produced instead of postulated a priori, in contrast to classical kinetic models based on a velocity filtration mechanism.

arXiv comment6 pages, 3 figures, aa LATeX class. Accepted for publication in Astronomy and Astrophysics as a Letter

References in corpus (30)

• On Solving the Coronal Heating Problem
• Characterizing interstellar filaments with Herschel in IC5146
• Hot Explosions in the Cool Atmosphere of the Sun
• An Ab Initio Approach to the Solar Coronal Heating Problem
• Nonlinear Dynamics of the Parker Scenario for Coronal Heating
• Electrons in the Young Solar Wind: First Results from the Parker Solar Probe
• Dynamics and thermodynamics of a simple model similar to self-gravitating systems: the HMF model
• Magnetic Reconnection as the Driver of the Solar Wind
• The Unresolved Fine Structure Resolved - IRIS observations of the Solar Transition Region
• A transonic collisionless model of the solar wind
• The solar chromosphere at high resolution with IBIS. IV. Dual-line evidence of heating in chromospheric network
• Turbulent coronal heating and the distribution of nanoflares
• A Chandra archival study of the temperature and metal abundance profiles in hot Galaxy Clusters at 0.1 < z < 0.3
• Current Sheets Formation in Tangled Coronal Magnetic Fields
• Broad Non-Gaussian Fe XXIV Line Profiles in the Impulsive Phase of the 2017 September 10 X8.3 class Flare Observed by Hinode/EIS
• Fine-scale explosive energy release at sites of prospective magnetic flux cancellation in the core of the solar active region observed by Hi-C 2.1, IRIS and SDO
• The Insignificance of Global Reheating in the Abell 1068 Cluster: X-Ray Analysis
• Non-Maxwellian analysis of the transition-region line profiles observed by the Interface Region Imaging Spectrograph
• Solar Chromospheric Temperature Diagnostics: a joint ALMA-H$\alpha$ analysis
• Phase mixing and wave heating in a complex coronal plasma
• Polytropic models of filamentary interstellar clouds - I. Structure and stability
• Temperature inversion in long-range interacting systems
• Response of the solar atmosphere to magnetic field evolution in a coronal hole region
• Surprises from quenches in long-range interacting systems: Temperature inversion and cooling
• Velocity filtration and temperature inversion in a system with long-range interactions
• Dynamical origin of non-thermal states in galactic filaments
• Violent relaxation in the Hamiltonian Mean Field model: I. Cold collapse and effective dissipation
• IBIS-A: The IBIS data Archive. High resolution observations of the solar photosphere and chromosphere with contextual data
• Kinetic and hydrodynamic regimes in multi-particle-collision dynamics of a one-dimensional fluid with thermal walls
• A Solar Magnetic-fan Flaring Arch Heated by Non-thermal Particles and Hot Plasma from an X-ray Jet Eruption

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