Corrugated Features in Coronal-mass-ejection-driven Shocks: A Discussion on the Predisposition to Particle Acceleration

Abstract

The study of the acceleration of particles is an essential element of research in the heliospheric science.Here, we discuss the predisposition to the particle acceleration around coronal mass ejections (CMEs)driven shocks with corrugated wave-like features. We adopt these attributes on shocks formed from disturbances due to the bimodal solar wind, CME deflection, irregular CME expansion, and the ubiquitous fluctuations in the solar corona. In order to understand the role of a wavy shock in particle acceleration, we define three initial smooth shock morphologies each one associated with a fast CME. Using polar Gaussian profiles we model these shocks in the low corona. We establish the corrugated appearance on smooth shock by using combinations of wave-like functions that represent the disturbances from medium and CME piston. For both shock types, smooth and corrugated, we calculate the shock normal angles between the shock normal and the radial upstream coronal magnetic field in order to classify the quasi-parallel and quasi-perpendicular regions. We consider that corrugated shocks are predisposed to different process of particle acceleration due to irregular distributions of shock normal angles around of the shock. We suggest that disturbances due to CME irregular expansion may be a decisive factor in origin of particle acceleration. Finally, we regard that accepting these features on shocks may be the start point for investigating some questions in the sheath and shock, like downstream-jets, instabilities, shock thermalization, shock stability, and injection particle process.

Kelvin–Helmholtz Instability and Alfvénic Vortex Shedding in Solar Eruptions

“…For larger scale eruptions, the magnetic field could be strong enough so that KHI develops less frequently closer to the solar surface. However, depending on the properties of the eruption, KHI could also develop away from the lower solar atmosphere, during the eruption's expansion and propagation inside the solar wind (Páez et al 2017), as the shearing between a CME and the solar wind could be appropriate for the formation of KHI (Manchester et al 2005). Therefore our results should be applicable to larger scale eruptions showing KHI either closer or further away from the solar surface.…”