Measures of correlation length at quasi-parallel and quasi-perpendicular shocks
Presentation Type
Talk
Presenter Format
Virtual Meeting Talk
Topic
Fundamental Processes in Comparative Magnetospheres
Start Date
13-5-2022 3:00 PM
Abstract
The solar wind and magnetosheath are known to be turbulent plasmas containing an energy cascade across a wide range of scales, the largest of which is the stirring scale. From recent observations and simulations of Earth’s bow shock, we have seen that there is a disordered or turbulent transition region containing reconnecting current sheets. This raises two key questions: Is there a link between the turbulent reconnection observed in the magnetosheath and the shock? How do properties of the turbulence, such as the stirring scale, evolve as solar wind plasma crosses the bow shock? We present two case studies of quasi-parallel and quasi-perpendicular bow shock crossings observed by Magnetospheric Multiscale (MMS). We measure changes in the stirring scale of the turbulence through the bow shock using combined magnetic field measurements from both the flux gate (FGM) and search coil (SCM) magnetometers. The stirring scale is quantified using the correlation length, where the influence of the shock ramp is reduced using a high pass filter. We find that the bow shock transition region is coincident with a reduction in peak correlation length by an approximate factor of ten, while the average correlation length is approximately halved compared to the solar wind closely preceding the shock.
Measures of correlation length at quasi-parallel and quasi-perpendicular shocks
The solar wind and magnetosheath are known to be turbulent plasmas containing an energy cascade across a wide range of scales, the largest of which is the stirring scale. From recent observations and simulations of Earth’s bow shock, we have seen that there is a disordered or turbulent transition region containing reconnecting current sheets. This raises two key questions: Is there a link between the turbulent reconnection observed in the magnetosheath and the shock? How do properties of the turbulence, such as the stirring scale, evolve as solar wind plasma crosses the bow shock? We present two case studies of quasi-parallel and quasi-perpendicular bow shock crossings observed by Magnetospheric Multiscale (MMS). We measure changes in the stirring scale of the turbulence through the bow shock using combined magnetic field measurements from both the flux gate (FGM) and search coil (SCM) magnetometers. The stirring scale is quantified using the correlation length, where the influence of the shock ramp is reduced using a high pass filter. We find that the bow shock transition region is coincident with a reduction in peak correlation length by an approximate factor of ten, while the average correlation length is approximately halved compared to the solar wind closely preceding the shock.
