Abstract

Decades of solar magnetic field observations have yielded a large amount of data with which to constrain dynamo models. However, a comprehensive theory of magnetic field generation in low-mass stars is currently still out of reach. Although these observations offer a picture of the Sun’s magnetic field with high spatial and temporal resolution, they suffer from the fact that they probe only one object. As such, they offer no information on how factors such as stellar mass or rotation affect dynamo processes. In this talk, I will cover how spectropolarimetry can be used to reconstruct the large-scale photospheric magnetic field strengths and geometries of low-mass stars – a technique known as Zeeman-Doppler Imaging. I will then review the main results obtained with Zeeman-Doppler Imaging and the constraints that these results can offer to dynamo modelling. I will pay particular attention to how magnetic field properties vary across the HR diagram as well as the temporal evolution of the magnetic fields of low-mass stars on both activity cycle time-scales and evolutionary time-scales.