Simulations of the KelvinHelmholtz instability driven by coronal mass ejections in the turbulent corona
Abstract
Recent high resolution AIA/SDO images show evidence of the development of the KelvinHelmholtz instability, as coronal mass ejections (CMEs) expand in the ambient corona. A largescale magnetic field mostly tangential to the interface is inferred, both on the CME and on the background sides. However, the magnetic field component along the shear flow is not strong enough to quench the instability. There is also observational evidence that the ambient corona is in a turbulent regime, and therefore the criteria for the development of the instability are apriori expected to differ from the laminar case. To study the evolution of the KelvinHelmholtz instability with a turbulent background, we perform threedimensional simulations of the incompressible magnetohydrodynamic equations. The instability is driven by a velocity profile tangential to the CMEcorona interface, which we simulate through a hyperbolic tangent profile. The turbulent background is generated by the application of a stationary stirring force. We compute the instability growthrate for different values of the turbulence intensity, and find that the role of turbulence is to attenuate the growth. The fact that the KelvinHelmholtz instability is observed, sets an upper limit to the correlation length of the coronal background turbulence.
 Publication:

arXiv eprints
 Pub Date:
 August 2014
 DOI:
 10.48550/arXiv.1408.2598
 arXiv:
 arXiv:1408.2598
 Bibcode:
 2014arXiv1408.2598G
 Keywords:

 Astrophysics  Solar and Stellar Astrophysics