The future location of auroral zones as described by the geomagnetic field of internal origin

The internal component of the geomagnetic field (generated within the Earth's core) is of crucial importance in modulating the impact of space weather events. Although primarily a dipolar field of slowly decreasing intensity, multipolar components can cause changes on interannual time-scales that are important for space weather applications. Of particular importance for space weather application is the location of the auroral oval, the region where it is most likely to see polar auroras. The auroral zone can be defined as a time-averaged auroral oval and it is possible to describe it via the internal geomagnetic field.

To be able to forecast interannual and decadal changes of the auroral oval location can benefit the design of future space missions and the planning of mitigation strategies for countries particularly exposed to severe space weather events (such as the UK).

Here we combine various future evolution scenarios for the geomagnetic field of internal origin with a definition of the auroral zones that rests on the calculation of non-orthogonal, magnetic coordinates. This methodology agrees well with calculations based on more complete magnetospheric and ionospheric physics. We apply our methodology to derive quantitative forecasts for the auroral zones' location over the next decades.