Würzburg 2018 – scientific programme
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EP: Fachverband Extraterrestrische Physik
EP 4: Sun and Heliosphere II - Dynamics (MHD, Particles)
EP 4.1: Talk
Wednesday, March 21, 2018, 11:00–11:15, BSZ - Pabel HS
Properties of a Small-scale Short-duration Solar Eruption with a Driven Shock — •Beili Ying1,2, Li Feng1, and Lei Lu1 — 1Purple Mountain Observatory, CAS, Nanjing, China — 2Max-Planck-Institut für Sonnensystemforschung, Göttingen
Large-scale solar eruptions have been extensively explored over many years. However, the properties of small-scale events with associated shocks have been rarely investigated. We present the analyses of a small-scale short-duration event. The impulsive phase of the M1.9-class flare lasted only for 4 minutes. The kinematic evolution of the CME hot channel reveals some exceptional characteristics including a very short duration of the main acceleration phase (<2 minutes), a rather high maximal acceleration rate (50 km s−2) and peak velocity (1800 km s−1). The fast and impulsive kinematics subsequently results in a shock related to a metric type II radio burst with a high starting frequency of 320 MHz of the fundamental band. Through the band split of the type II burst, the shock compression ratio decreases from 2.2 to 1.3, and the magnetic field strength of the shock upstream region decreases from 13 to 0.5 Gauss at heights of 1.1 to 2.3 R⊙. We find that the CME (4*1030 erg) and flare (1.6*1030 erg) consume similar amount of magnetic energy. The same conclusions having been drawn for large-scale eruptions imply that small- and large-scale events possibly share the similar relationship between CMEs and flares. The kinematic particularities of this event are possibly related to the small footpoint-separation distance of the associated magnetic flux rope, as predicted by the Erupting Flux Rope model.