Enthalpy-based modeling of tomographically reconstructed quiet-Sun coronal loops

MAC CORMACK, C.; LÓPEZ FUENTES, M.; MANDRINI, C.H.; LLOVERAS, D.; VÁSQUEZ, A.M.

ADVANCES IN SPACE RESEARCH

ELSEVIER SCI LTD

Año: 2022

0273-1177

The structure of the solar corona is made of magneticflux tubes or loops. Due to the lack of contrast with their environment,observing and studying coronal loops in the quiet Sun is extremely difficult.In this work we use a differential emission measure tomographic (DEMT)technique to reconstruct, from a series of EUV images covering an entire solarrotation, the average 3D distribution of the thermal properties of the coronalplasma. By combining the DEMT products with extrapolations of the globalcoronal magnetic field, we reconstruct coronal loops and obtain the energyinput required to keep them at the typical million-degree temperatures of thecorona. We statistically study a large number of reconstructed loops forCarrington rotation (CR) 2082 obtaining a series of typical average loops ofdifferent lengths. We look for relations between the thermal properties and thelengths of the constructed typical loops and find similar results to thosefound in a previous work (Mac Cormack et al., 2020).. We also analyze thetypical loop properties by comparing them with the zero-dimensional (0D)hydrodynamic model Enthalpy-Based Thermal Evolution of Loops (EBTEL, Klimchuket al., 2008). We explore two heating scenarios. In the first one, we apply aconstant heating rate assuming that typical loops are in quasi-static equilibrium.In the second scenario we heat the plasma in the loops using short impulsiveevents. We find that the reconstructed typical loops are overdense with respectto quasi-static equilibrium solutions of the hydrodynamic model. Impulsiveheating, on the other hand, reproduces better the observed densities andtemperatures for the shorter and approximately semicircular loops. The thermalproperties of longer loops cannot be correctly reproduced with the EBTEL model.We suggest that to properly assess the physical characteristics of the analyzedloops in future works, it would be necessary to use a more sophisticated 1Dmodel, with which to study the loop temperature and density profiles and testlocalized heating at different locations along the loops.