Small-scale heating events in the solar atmosphere

II. Lifetime, total energy, and magnetic properties

¹ Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
e-mail: nuno.guerreiro@pmodwrc.ch
² Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway

Received: 27 September 2016
Accepted: 4 April 2017

Abstract

Context. Small-scale heating events (SSHEs) are believed to play a fundamental role in understanding the process responsible for heating of the solar corona, the pervading redshifts in the transition region, and the acceleration of spicules.

Aims. We determine the properties of the SSHEs and the atmospheric response to them in 3D magnetohydrodynamics (3D-MHD) simulations of the solar atmosphere.

Methods. We developed a method for identifying and following SSHEs over their lifetime, and applied it to two simulation models. We identified the locations where the energy dissipation is greatest inside the SSHEs volume, and we traced the SSHEs by following the spatial and temporal evolution of the maximum energy dissipation inside the SSHEs volume.

Results. The method is effective in following the SSHEs. We can determine their lifetime, total energy, and properties of the plasma, as well as the magnetic field orientation in the vicinity of the SSHEs.

Conclusions. We determine that the SSHEs that have the potential to heat the corona live less than 4 min, and typically the energy they release ranges from 10²⁰ to 10²⁴ erg. In addition, the directional change of the field lines on the two sides of the current sheet constituting the SSHEs ranges from 5° to 15° at the moment of the absolute maximum energy dissipation.