Speaker
Description
The surface magnetic fields of cool stars are inherently multi-scale, dominated by small-scale structures while also hosting weaker large-scale components. Historically, these two aspects of stellar magnetism have been studied in isolation, using distinct diagnostic techniques—Zeeman broadening for small-scale fields and spectropolarimetry for large-scale fields. This separation has led to a fragmented understanding of stellar magnetism, with these methods often producing highly discordant field strength measurements. We present our ongoing research aimed at bridging this divide by unifying small- and large-scale magnetic field measurements within a single modelling framework. Achieving this requires both higher-quality observations, particularly in the near-infrared, and the development of advanced computational techniques capable of capturing the inherently multi-scale nature of stellar magnetic fields. We demonstrate the first results of applying this integrated approach to active solar-type stars and M dwarfs. These results reveal significantly revised perspectives on the geometry and structure of cool-star magnetic fields, offering a more complete and coherent observational picture of stellar magnetism. Our findings underscore the importance of a unified methodology for advancing our understanding of stellar magnetic phenomena and their broader astrophysical implications.