Heating and cooling of coronal loops with turbulent suppression of parallel heat conduction

Abstract

Using the "enthalpy-based thermal evolution of loops" (EBTEL) model, we investigate the hydrodynamics of the plasma in a flaring coronal loop in which heat conduction is limited by turbulent scattering of the electrons that transport the thermal heat flux. The EBTEL equations are solved analytically in each of the two (conduction-dominated and radiation-dominated) cooling phases. Comparison of the results with typical observed cooling times in solar flares shows that the turbulent mean free-path ${\lambda }_T$ lies in a range corresponding to a regime in which classical (collision-dominated) conduction plays at most a limited role. We also consider the magnitude and duration of the heat input that is necessary to account for the enhanced values of temperature and density at the beginning of the cooling phase and for the observed cooling times. We find through numerical modeling that in order to produce a peak temperature $\simeq 1.5\times 10^7$~K and a 200~s cooling time consistent with observations, the flare heating profile must extend over a significant period of time; in particular, its lingering role must be taken into consideration in any description of the cooling phase. Comparison with observationally-inferred values of post-flare loop temperatures, densities, and cooling times thus leads to useful constraints on both the magnitude and duration of the magnetic energy release in the loop, as well as on the value of the turbulent mean free-path ${\lambda }_T$.

arXiv comment16 pages, 4 figures, to be published in The Astrophysical Journal

References in corpus (12)

• Radiative Hydrodynamic Models of the Optical and Ultraviolet Emission from Solar Flares
• Highly Efficient Modeling of Dynamic Coronal Loops
• A Unified Computational Model for Solar and Stellar Flares
• Enthalpy-based Thermal Evolution of Loops: II. Improvements to the Model
• Turbulent kinetic energy in the energy balance of a solar flare
• Implications for electron acceleration and transport from non-thermal electron rates at looptop and footpoint sources in solar flares
• Turbulent pitch-angle scattering and diffusive transport of hard-X-ray producing electrons in flaring coronal loops
• Properties of the Acceleration Regions in Several Loop-structured Solar Flares
• Decay Phase Cooling and Inferred Heating of M- and X-class Solar Flares
• Suppression of parallel transport in turbulent magnetized plasmas and its impact on non-thermal and thermal aspects of solar flares
• The role of diffusion in the transport of energetic electrons during solar flares
• Anomalous Cooling of Coronal Loops with Turbulent Suppression of Thermal Conduction

Cited by in corpus (12)

• Slow-Mode Magnetoacoustic Waves in Coronal Loops
• Si IV Resonance Line Emission During Solar Flares: Non-LTE, Non-equilibrium, Radiation Transfer Simulations
• The Atmospheric Response to High Nonthermal Electron Beam Fluxes in Solar Flares. II. Hydrogen Broadening Predictions for Solar Flare Observations with the Daniel K. Inouye Solar Telescope
• Effect of transport coefficients on excitation of flare-induced standing slow-mode waves in coronal loops
• Electron Beams Cannot Directly Produce Coronal Rain
• Two-Phase Heating in Flaring Loops
• On quasi-parallel whistler waves in the solar wind
• Coronal Loop Scaling Laws for Various Forms of Parallel Heat Conduction
• A Model for Gradual Phase Heating Driven by MHD Turbulence in Solar Flares
• Scaling Laws for Dynamic Solar Loops
• An investigation of flare emissions at multiple wavelengths
• Temperature and Differential Emission Measure Profiles in Turbulent Solar Active Region Loops