HYPERION simulation results of (left) temperature isosurfaces and magnetic field lines and (right) loop summit radiation details in a coronal loop, superimposed on an SDO image of coronal loops
HYPERION simulation results of (left) temperature isosurfaces and magnetic field lines and (right) loop summit radiation details in a coronal loop, superimposed on an SDO image of coronal loops

Objective
Magnetohydrodynamic (MHD) turbulence has long been proposed as a mechanism for the heating of coronal loops in the framework of the Parker scenario for coronal heating. So far most studies have focused on its dynamical properties without considering its thermodynamical and radiative features because of the very demanding computational requirements. We aim to extend this previous research to the compressible regime using HYPERION, a new parallelized, visco-resistive, three-dimensional compressible MHD code.

Approach

  • Model solar coronal loop in Cartesian geometry
  • Utilize a three-dimensional compressible MHD model with magnetic reconnection, field-wise thermal conduction, and optically thin radiation based on the CHIANTI atomic database for spectroscopic diagnostics of astrophysical plasmas which includes the wavelength range that contributes significantly to the total radiative output of the Sun
  • Discretize equations with a Fourier-collocation—finite-difference scheme in space, and a time-step split third-order Runge-Kutta—forward Euler method in time. Parallelize the code for HPC with MPI
  • Use data analysis techniques developed for the EUV Imaging Spectrograph on the Hinode satellite to post-process the HYPERION solutions and compare with solar data

Deliverable/Value/Accomplishment

  • We show that the dissipative terms in the energy equation, resulting from the coronal dynamics induced by appropriate photospheric motions, represent a heating term able to balance the thermal conduction parallel to the DC magnetic field and the radiative emission
  • The resulting temperature and density profiles, showing a temporal and spatial intermittency, demonstrate the efficiency of the DC heating mechanism, leading to properties that are characteristic of the Sun’s chromosphere/transition region/corona system