Study of slow-mode shocks in magnetic reconnection based on hybrid simulations and satellite observations
Presentation Type
Talk
Presenter Format
Virtual Meeting Talk
Topic
Fundamental Processes in Comparative Magnetospheres
Start Date
13-5-2022 1:45 PM
Abstract
Petschek’s model of reconnection has reconnection rate comparable to in-situ observations, and it has a small diffusion region which is flanked by two slow-mode shocks on each side of the exhaust. This study explores the existence of slow-mode shocks in magnetic reconnection with both 2.5 D hybrid simulations and Magnetospheric MultiScale (MMS) observations. We use the six Rankine-Hugoniot conditions and the six specific conditions for slow-mode shocks to analyze the presence of slow-mode shocks in both simulations and in-situ satellite observations. We observe that the reconnection boundary can be interpreted as a slow-mode shock from as close as ~9 ion inertial lengths from the X-point. The detection of slow-mode shocks increases with increasing distance from the X-point and with increasing ion plasma beta [Walia et. al., 2022]. The change in beta leads to the change in turbulence, thus causing a decrease in the detection of slow-mode shocks as the turbulence increases. Some dependence of occurrence of slow-mode shocks is also found on the ion to electron pressure ratio. Additionally, we observe that if the slow-mode shocks are analyzed by taking artificial satellite cuts in the simulations at various angles, the detection percentage of slow-mode shocks can decrease to ∼10% for very oblique crossings. In the near-Earth magnetotail crossings of MMS, 28 out of 51 crossings are observed to have slow-mode shocks. The number of detections of slow-mode shocks in the near-Earth magnetotail (55%), and in hybrid simulations, suggests that they are a prominent part of magnetic reconnection geometry.
Study of slow-mode shocks in magnetic reconnection based on hybrid simulations and satellite observations
Petschek’s model of reconnection has reconnection rate comparable to in-situ observations, and it has a small diffusion region which is flanked by two slow-mode shocks on each side of the exhaust. This study explores the existence of slow-mode shocks in magnetic reconnection with both 2.5 D hybrid simulations and Magnetospheric MultiScale (MMS) observations. We use the six Rankine-Hugoniot conditions and the six specific conditions for slow-mode shocks to analyze the presence of slow-mode shocks in both simulations and in-situ satellite observations. We observe that the reconnection boundary can be interpreted as a slow-mode shock from as close as ~9 ion inertial lengths from the X-point. The detection of slow-mode shocks increases with increasing distance from the X-point and with increasing ion plasma beta [Walia et. al., 2022]. The change in beta leads to the change in turbulence, thus causing a decrease in the detection of slow-mode shocks as the turbulence increases. Some dependence of occurrence of slow-mode shocks is also found on the ion to electron pressure ratio. Additionally, we observe that if the slow-mode shocks are analyzed by taking artificial satellite cuts in the simulations at various angles, the detection percentage of slow-mode shocks can decrease to ∼10% for very oblique crossings. In the near-Earth magnetotail crossings of MMS, 28 out of 51 crossings are observed to have slow-mode shocks. The number of detections of slow-mode shocks in the near-Earth magnetotail (55%), and in hybrid simulations, suggests that they are a prominent part of magnetic reconnection geometry.
