Welcome

Hi, whoever you are! Welcome to my website!

I am a researcher in helio- and asteroseismology, focussing on the interplay between acoustic oscillations and stellar magnetic activity.

Currently, I am entrusted with the setup of a solar MCAO system.

Cheers,
René

Hi, whoever you are! Welcome to my website!

I am a researcher in helio- and asteroseismology, focussing on the interplay between acoustic oscillations and stellar magnetic activity. Here I will try to provide some basic introductions into these exciting topics, information on my past and present projects, access to papers, presentations, and posters that I have created.

If you landed on this website and find very little content: I am working on it.

Cheers,
René

Current Project

Setup of a Prototype of a Solar Multi-Conjugated Adaptive Optics System

I am responsible for the optical design and setup of a prototype of a multi-conjugate adaptive optics system. I did the optical design in Zemax.

With this prototype, one deformable mirror (DM) is at a conjugate of the entrance pupil and four DMs are at conjugate heights along the line of sight at various distances within the Earth’s atmosphere. The instrument will be able to correct a field-of-view of 40′′.

On the left, you can see a 3D rendering of the four deformable mirrors on their mounting. This mount and the figure was designed by Miguel Estevez Perez.

The purpose of the prototype is to test and verify a scaled-down version of the design for the future European Solar Telescope MCAO. After being tested in our lab at KIS in Freiburg, the system will be set up at the GREGOR telescope on Tenerife.

Research Highlight

Activity-related Variation of Solar p-Mode Energy Supply Rates

So far, it was believed that the solar acoustic oscillations are fed with energy at a constant rate throughout the Sun’s magnetic activity cycle. With a careful re-analysis of 25 years of GONG data, I was able the show that this is indeed not the case:

The energy supply rate of solar p-modes is strongly anti-correlated with the level of solar magnetic activity!

The plot shows the weighted average of over 1200 oscillation multiplets’ fractional change of their energy supply rate. Note that there are error bars on the data point, they are just rather small.

These results have been published in Kiefer & Broomhall, 2021, MNRAS 500.3:3095.