Sted: Det Norske Videnskaps-Akademi
20. september 2012 kl 17:30
Mapping and Predicting the Aurora
Professor Patricia Reiff, Rice University, holder årets Birkelandforelesning. Åpent for alle interesserte.
Advances in understanding, mapping, and even predicting the aurora have made major strides in the past 25 years. From early work by Birkeland and even Benjamin Franklin, to rocket, radar, and spacecraft (particularly multiple spacecraft), we have learned more about the location, acceleration mechanisms, and mapping to the Earth's magnetotail.
With multiple spacecraft we have been able to show that the "inverted-V" type aurora is indeed caused by auroral acceleration by parallel electric fields, and that diffuse aurora is caused by pitch angle scattering of trapped electrons in the magnetotail.
In addition, "wave accelerated" auroras can also be observed near the boundary between open and closed magnetic fields. Advances in predicting the aurora go hand in hand with predicting geomagnetic activity indices such as Kp, AE, and Dst.
At Rice University we have developed algorithms based on a neural network using solar wind and Interplanetary Magnetic Field input that can predict Kp, AE and Dst 3 and even 6 hours ahead (http://mms.rice.edu/realtime/forecast.html), where users can sign up for a free email notification of events. In parallel, The Johns Hopkins University's Applied Physics Laboratory has an auroral prediction algorithm that can provide a georeferenced auroral map 45 minutes in advance. We hope to merge the two techniques in the near future, yielding an accurate georeferenced auroral prediction up to 3 hours in advance.