Abstract
The role of magnetic reconnection on the evolution of the Kelvin–Helmholtz instability is investigated in a plasma configuration with a velocity shear field. It is shown that the rate at which the large-scale dynamics drives the formation of steep current sheets, leading to the onset of secondary magnetic reconnection instabilities, and the rate at which magnetic reconnection occurs compete in shaping the final state of the plasma configuration. These conclusions are reached within a two-fluid plasma description on the basis of a series of two-dimensional numerical simulations. Special attention is given to the role of the Hall term. In these simulations, the boundary conditions, the symmetry of the initial configuration and the simulation box size have been optimized in order not to affect the evolution of the system artificially.
Highlights
Magnetic field line reconnection is a fundamental physical process in a magnetized plasma and is able to reorganize the large-scale topology of the magnetic field and to affect the global plasma energy balance of the system at the same time
As mentioned above, we have assumed that the relevant microphysics effect in the generalized Ohm’s law that breaks the coupling between the electron and the magnetic field evolution is given by electron inertia so that magnetic reconnection takes place only when the de-scale is reached
In plasma configurations with not too small values of the β parameter, defined as the ratio between the plasma and the magnetic pressure, the wider ion decoupling region allows the ion inflow velocity at the reconnection point to be comparable with the local Alfvén velocity, and allows magnetic reconnection to occur on faster timescales [1]–[7] than predicted by a single fluid description
Summary
Magnetic field line reconnection is a fundamental physical process in a magnetized plasma and is able to reorganize the large-scale topology of the magnetic field and to affect the global plasma energy balance of the system at the same time. Large-scale (as compared to the ion skin depth di) vortices are essentially MHD structures, their motion is able to create favorable conditions for reconnection to act, i.e. to generate magnetic inversion layers, but it is able to build up sub-di current sheets, within which processes characteristic of two-fluid dynamics can develop. When such sub-di current layers are created, fast magnetic reconnection can occur [8, 28]. If the in-plane magnetic tension is too high, the large-scale evolution of the vortices is not able to develop such small scales and the system exhibits essentially MHD behavior during all its evolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
