Evidence for a highly non-dipolar character of the European 800 AD event

International audienceOver the last years new evidences of several short-lived regional maxima of the geomagnetic field intensity atvarious times and locations have been defined. These features have important implications both for geomagneticfield modeling and for Earth0s dynamo simulations. However, the nature, extent and underlying causes of thesevariations are still poorly understood. Here we present a detailed analysis of the sharp abrupt intensity change thattook place in Western Europe around 800 AD, the most significant geomagnetic field intensity feature observedin Europe over the last two millennia. For this purpose we present an up-to-date regional intensity reconstructionfor Western Europe and compare the results with other regional and global geomagnetic field reconstructions. Theresults indicate that the 800 AD event is mainly controlled by non-dipolar geomagnetic source