Testing the estimated hypothetical response of a major CME impact on Earth and its implications to space weather

Abstract

The high-speed coronal mass ejection (CME), ejected on 23 July 2012, observed by STEREO-A on the same day as the leading edge of the CME arrived at 1AU was unique both in respect to the observed plasma and magnetic structure and the large solar energetic particle flux that dynamically regulated the shock front. Because of its great intensity, it has been hailed as “Carrington 2” by some, warning that, had that CME been heading toward the Earth, it might have caused a major space weather event. We used the Rice Artificial Neural Network algorithms with the solar wind and interplanetary magnetic field parameters measured in situ by STEREO-A as inputs to infer what the “geoeffectiveness” of that storm might have been. We have also used an MHD model in Open Geospace General Circulation Model to understand the global magnetospheric process in time sequence. We presently show our neural network models of Kp and Dst on our real-time prediction site: http://mms.rice.edu/realtime/forecast.html. Running this event through our models showed that, in fact, this would have been an exceptional event. Our results show a prediction resulting in a Kp value of 8+, a Dst of nearly −250 nT, but when assumptions about maximum dipole angle tilt and density are made, predictions resulting in Kp of 11− and Dst dipping close to −700 nT are found. Finally, when solar energetic proton flux is included, the Kp and Dst predictions drop to 8− and ≈−625 nT, respectively.