Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas
In a collisionless plasma, when reconnection instability takes place, strong shear flows may develop. Under appropriate conditions these shear flows become unstable to the Kelvin-Helmholtz instability. Here, we investigate the coupling between these instabilities in the framework of a four-field mod...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2009-04-01
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| Series: | Nonlinear Processes in Geophysics |
| Online Access: | http://www.nonlin-processes-geophys.net/16/241/2009/npg-16-241-2009.pdf |
| _version_ | 1811266506652123136 |
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| author | D. Grasso D. Borgogno F. Pegoraro E. Tassi |
| author_facet | D. Grasso D. Borgogno F. Pegoraro E. Tassi |
| author_sort | D. Grasso |
| collection | DOAJ |
| description | In a collisionless plasma, when reconnection instability takes place, strong shear flows may develop. Under appropriate conditions these shear flows become unstable to the Kelvin-Helmholtz instability. Here, we investigate the coupling between these instabilities in the framework of a four-field model. Firstly, we recover the known results in the low β limit, β being the ratio between the plasma and the magnetic pressure. We concentrate our attention on the dynamical evolution of the current density and vorticity sheets which evolve coupled together according to a laminar or a turbulent regime. A three-dimensional extension in this limit is also discussed. Secondly, we consider finite values of the β parameter, allowing for compression of the magnetic and velocity fields along the ignorable direction. We find that the current density and vorticity sheets now evolve separately. The Kelvin-Helmholtz instability involves only the vorticity field, which ends up in a turbulent regime, while the current density maintains a laminar structure. |
| first_indexed | 2024-04-12T20:44:28Z |
| format | Article |
| id | doaj.art-0df3d046fed54af791d65ce9e1fd3584 |
| institution | Directory Open Access Journal |
| issn | 1023-5809 1607-7946 |
| language | English |
| last_indexed | 2024-04-12T20:44:28Z |
| publishDate | 2009-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Nonlinear Processes in Geophysics |
| spelling | doaj.art-0df3d046fed54af791d65ce9e1fd35842022-12-22T03:17:18ZengCopernicus PublicationsNonlinear Processes in Geophysics1023-58091607-79462009-04-01162241249Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmasD. GrassoD. BorgognoF. PegoraroE. TassiIn a collisionless plasma, when reconnection instability takes place, strong shear flows may develop. Under appropriate conditions these shear flows become unstable to the Kelvin-Helmholtz instability. Here, we investigate the coupling between these instabilities in the framework of a four-field model. Firstly, we recover the known results in the low β limit, β being the ratio between the plasma and the magnetic pressure. We concentrate our attention on the dynamical evolution of the current density and vorticity sheets which evolve coupled together according to a laminar or a turbulent regime. A three-dimensional extension in this limit is also discussed. Secondly, we consider finite values of the β parameter, allowing for compression of the magnetic and velocity fields along the ignorable direction. We find that the current density and vorticity sheets now evolve separately. The Kelvin-Helmholtz instability involves only the vorticity field, which ends up in a turbulent regime, while the current density maintains a laminar structure.http://www.nonlin-processes-geophys.net/16/241/2009/npg-16-241-2009.pdf |
| spellingShingle | D. Grasso D. Borgogno F. Pegoraro E. Tassi Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas Nonlinear Processes in Geophysics |
| title | Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas |
| title_full | Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas |
| title_fullStr | Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas |
| title_full_unstemmed | Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas |
| title_short | Coupling between reconnection and Kelvin-Helmholtz instabilities in collisionless plasmas |
| title_sort | coupling between reconnection and kelvin helmholtz instabilities in collisionless plasmas |
| url | http://www.nonlin-processes-geophys.net/16/241/2009/npg-16-241-2009.pdf |
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