We have developed a simple and cost-efficient algorithm to model top-down solar forcing by variations in the electromagnetic radiation of the sun and in the geomagnetic forcing in chemistry-climate models based on the simplified stratospheric ozone scheme LINOZ v3 in ICON-ART.

Electrons from the ring currents and radiation belts accelerated to hundreds of keV precipitate into the atmosphere during geomagnetic storms. This precipitating flux and the ensuing atmospheric ionization are modelled here with a magnetospheric model, considering different acceleration mechanism within the ring currents.

M-stars like Trappist can be much more active than the sun. But how does that affect possible atmospheres of planets in orbit around such starts? And, will that have an impact on the detectability of biosignatures like ozone?

This is explored in a recent publications exemplarily for the exoplanet Trappist 1e.

Even the largest solar proton events of the last 70 years had a relatively small impact on the atmosphere below 30 km altitude. But what would happen if a much larger solar event as occurred, e.g., in paleonucleid records in AD774/775? We investigated the impact on atmospheric composition and the change in UV radiation at the surface.

Exceptionally electron precipitation was observed by a research balloon on December 14, 2009, in magnetic mid-latitudes. Trace gas observations confirm that precipitation in midlatitudes probably took place, despite low geomagnetic activity.