Department: Sun and Heliosphere
The research field of the department „Sun and Heliosphere“ comprises the Sun with its full variety of observable and measurable phenomena. The focus is on the atmosphere of the Sun with its rich structure and dynamics, complemented on the one hand by the investigation of the interior of the Sun as the location where the solar magnetic field is generated, and on the other hand by the exploration of the heliosphere, i.e. the inter-planetary space that is determined by the solar wind, and whose characteristics are again shaped by the solar atmosphere. The investigation of solar-terrestrial connections, especially of the impact of the variable radiation of solar particles and electromagnetic waves on the Earth, even extends the research area beyond the Sun and its close environment. The common topic, connecting all these strands and being the main driver for the multitude of dynamic solar features, is the solar magnetic field.
The development and construction of scientific instruments and the acquisition and analysis of measurement data are essential for the department. The outer atmosphere of the Sun, the corona, will be observed from space with optical instruments covering the full spectral range from visible to EUV (extreme UV), and its plasma characteristics are analyzed by spectroscopic means. The lower layers of the atmosphere, the photosphere and the chromosphere, are investigated by spectropolarimetric measurements and with imaging techniques from ground, from space and via stratospheric balloons. The relevant spectral range extends from millimeter waves to FUV (far UV). Main target of the measurements is to characterize the solar magnetic field that plays an essential role for the structure and dynamics of the atmosphere. Particles and waves in the solar wind are measured in-situ by space probes. The chemical composition and the distribution of the particles as well as the study of transport mechanisms and acceleration processes are of main interest.
The observational activities go along with intensive theoretical work. The focus is on numerical simulations of solar dynamo processes and of MHD processes in the convection zone and the atmosphere of the Sun.