Comparative study of the December 28, 2015 – January 2, 2016 and April 7 – 11, 1997 Sun-Earth connection events

Abstract: A Sun-Earth connection event started on December 28, 2015 in association with a M1.8 X-ray flare, commencing at 1120UT detected by the GOES Environmental satellites, and a partial halo coronal mass ejection (CME) observed from 1200UT by the SOHO LASCO coronographs. SDO AIA observations indicate that this event was located at W11S22. The related interplanetary coronal mass ejection (ICME) drove an above average strength fast-forward interplanetary shock observed by SC Wind, at the start of Dec 31. This shock also appears to have accelerated solar energetic particles (SEP); EPAC/ACE observations show that these energetic particles peaked at shock passage. The shock driver, i.e. the ICME, appears to have impacted the Earth’s environment near 17UT on December 31. This ICME seems to include several substructures and possibly extended to around midday on January 2, 2016. The impact of the ICME produced lively auroras at low Earth latitudes in the Western-North hemisphere [and it is to be checked if its Earth’s impact damaged hardware located on the Earth’s environment]. The associated strong magnetic storm was due to the leading part of the ICME maintaining a southward-oriented magnetic field for several hours.

The purpose of this study is to compare and contrast this event with the April 7-11, 1997 Sun-Earth connection event previously discussed by Berdichevsky et al. (1998) which included the passage of an ICME at Earth with a persistent northward, rather than southward, magnetic-field and produced an unusually long-lasting compression of the Earth’s magnetosphere.

^aBerdichevsky, D, J.-L. Bougeret, J.-P. Delaboudinière, N. Fox, M. Kaiser, R. Lepping, D. Michels, S. Plunkett, D. Reames, M. Reiner, I. Richardson, G. Rostoker, J. Steinberg, B. Thompson, and T. von Rosenvinge, Evidence for multiple ejecta: April 7-11, 1997, ISTP Sun-Earth connection event GRL, 25, 2473-6, 1998.