Numerical simulation of beam heating - dependency on initial atmosphere

Background

Flares and various energetic phenomena in the solar atmosphere (Ellerman bombs, UV-burst, jets) are believed to be caused by magnetic reconnection releasing stored magnetic energy in the form of non-thermal electrons that eventually transfer their energy to the surrounding plasma through collisons.

Peter et al 2014 reported: "The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for the chromosphere and corona that constitute the outer atmosphere, which is now considered a dynamic structured envelope. Recent observations by IRIS (Interface Region Imaging Spectrograph) reveal that it is difficult to determine what is up and down even in the cool 6000-K photosphere just above the solar surface: this region hosts pockets of hot plasma transiently heated to almost 100,000 K. The energy to heat and accelerate the plasma requires a considerable fraction of the energy from flares, the largest solar disruptions. These IRIS observations not only confirm that the photosphere is more complex than conventionally thought, but also provide insight into the energy conversion in the process of magnetic reconnection."

Goal

The goal of this project is to simulate the effects of electron beam heating in the solar upper atmosphere using the existing 1D radiation hydrodynamic code RADYN. Strong heating low down may reproduce the explosions reported by Peter et al (UV-bursts) and less violent heating may give rise to what has been called Ellermann bombs and jets. We will here especially study how different initial atmospheres lead to different effects.

Method

 

1. Extract a starting model from a Bifrost simulation by following field-lines from a site of strong heating.

 

 

Make the starting atmosphere consistent with the RADYN equations and EOS by following the steps in the RADYN manual.

 

2. Run with a small set of beam parameters.

 

 

Use dl=3, Ec=25 and a few fluxes from the range Flux_max=[3.e8, 1.e10]

Look at the atmosphere response and explain through an analysis of the terms in the energy equation (using emovie)