Seminar: Setting observational constraints to the chromospheric heating problem

  • Date: –15:00
  • Location: Ångströmlaboratoriet, Lägerhyddsvägen 1 90103Å and Zoom:
  • Lecturer: Jaime de la Cruz Rodríguez, Stockholm University
  • Contact person: Anish Amarsi
  • Seminarium

The solar atmosphere is hotter than predicted by assuming radiative equilibrium. This is most obviously evidenced by the high temperature of the solar corona, but the bulk of the energy deposition happens already down in the much cooler chromosphere. While in recent years we have gained detailed understanding of many important processes that must be at work in the chromosphere, also from numerical simulations, their exact contribution to the total energy budget remains unclear.

Chromospheric heating or cooling can be estimated by calculating the radiative losses whenever a model atmosphere is available. Most comparisons between simulations and observations have used canonical values of radiative losses that have been derived from 1D models of spatio-temporal averages of solar spectra (e.g., FAL / VAL models). Such approach cannot capture the high complexity and fine structures that is observed in high resolution observations.

In this talk, I will discuss the accuracy and challenges associated with the methods that we use to infer radiative losses from observations. I will also present our first spatially resolved maps of the radiative losses derived from very high spatial resolutions observations acquired with the Swedish 1-m Solar Telescope in the Ca II K, Ca II 8542 and Fe I 6301/6302 lines.


We will take the speaker to lunch at around 12.20, and there will be fika after the seminar.