Turbulence generation of ion scale in the presence of magnetic islands and guide field at the magnetopause region

Abstract

In the present work, turbulence generation due to the dynamic evolution of magnetic islands is investigated. The role of ambient magnetic field in the evolution of magnetic islands and turbulence generation is also investigated. The origin of magnetic islands lies in the fact that reconnection takes place in thin current sheets which becomes unstable and leads to the formation of magnetic islands. The model is developed using basic fluid equations and Maxwell’s equations to study the dynamics of magnetic islands. The dynamical equation has been solved numerically for two different cases: (a) background field consisting of Harris equilibrium field component only and (b) background field comprising of both axial and Harris equilibrium field. It is evident from our investigation that the evolution of magnetic islands establishes the presence of turbulence in reconnection sites. Using the simulation data, we have also examined the associated power spectrum which displays the distribution of energy in different wave modes. This spectral index has consistency with THEMIS observations (Chaston et al. 2008, Nat. Phys. 4, 19). In this way, the present approach may be helpful to understand the interplay between magnetic reconnection and turbulence in magnetopause region.