Predicting Ground Magnetic Disturbance Using Realistic Geospace Electric Currents

Abstract:

Electric currents in space are the primary driver of magnetic variations measured at Earth’s surface, which in turn induce geoelectric fields that present a significant natural hazard for technological systems like high-voltage power distribution networks. Previous studies have shown that large enhancements in geomagnetic fields can be extremely localized, in both time and space, and difficult to predict in any deterministic manner. Probabilistic predictions are possible given accurate data distributions, but a scarcity of geomagnetic observing systems makes it difficult to generate spatially continuous “hazard maps”. Global geospace models can help fill in the gaps, but only if they generate physically realistic electric current distributions. If this holds, synthetic data distributions can be generated for any location in the computational domain. The Lyon-Fedder-Mobarry (LFM) model was used to simulate the Whole Heliosphere Interval (WHI), one full rotation of the sun with two high-speed solar wind intervals, at various grid resolutions. We discuss the results in terms of probabilistic predictions of geomagnetic disturbance, and related projects for mapping storm-time geomagnetic activity.