Off-limb Solar Coronal Wavefronts From SDO/AIA EUV Observations - Implications For Particle Production

TL;DR

This study analyzes high-cadence off-limb solar coronal waves observed by SDO/AIA, revealing their kinematic properties, shock signatures, and potential links to energetic particle production near Earth.

Contribution

First detailed high-cadence imaging of off-limb coronal waves, linking their kinematics and shock nature to energetic particle events.

Findings

Initial wave velocities of ~1287 and ~736 km/s

Wave associated with weak shock signatures

Correlation between EUV waves and proton flux increases

Abstract

We derive kinematic properties for two recent solar coronal transient waves observed off the western solar limb with the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) mission. The two waves occurred over $\sim10$-min intervals on consecutive days - June 12 and 13, 2010. For the first time, off-limb waves are imaged with a high 12-sec cadence, making possible detailed analysis of these transients in the low corona between $\sim1.1$-2.0 solar radii ($R_{s}$). We use observations in the 193 and 211 {\AA} AIA channels to constrain the kinematics of both waves. We obtain initial velocities for the two fronts of $\sim1287$ and $\sim736$ km s$^{-1}$, and accelerations of $-1170$ and $-800$ m s$^{-2}$, respectively. Additionally, differential emission measure analysis shows the June 13 wave is consistent with a weak shock. EUV wave positions are correlated with positions from simultaneous type II radio burst observations. We find good temporal and height association between the two, suggesting that the waves may be the EUV signatures of coronal shocks. Furthermore, the events are associated with significant increases in proton fluxes at 1 AU, possibly related to how waves propagate through the coronal magnetic field. Characterizing these coronal transients will be key to connecting their properties with energetic particle production close to the Sun.