An Updated View of Solar Eruptive Flares and the Development of Shocks and CMEs: History of the 2006 December 13 GLE-Productive Extreme Event

Abstract

Abstract An extreme 2006 December 13 event marked the onset of the Hinode era, being the last major flare in the solar cycle 23 observed with NoRH and NoRP. The event produced a fast CME, strong shock, and a big particle event responsible for GLE70. We endeavor to clarify the relations between the eruptions, shock wave, and flare, and to shed light on a debate over the origin of energetic protons. One concept relates it to flare processes. Another one associates the acceleration of ions with a bow shock driven by a CME at (2-4)R⊙. The latter scenario is favored by a delayed particle release time after the flare. However, our previous studies have established that a shock wave is typically excited by an impulsively erupting magnetic rope (future CME core) during the flare rise, while the outer CME surface evolves from an arcade whose expansion is driven from inside. Observations of the 2006 December 13 event reveal two shocks following each other, whose excitation scenario contradicts the delayed CME-driven bowshock hypothesis. Actually, the shocks developed much earlier, and could accelerate protons still before the flare peak. Then, the two shocks merged into a single stronger one, and only decelerated and dampened long afterwards.