Evidence for ion-scale magnetic flux ropes generated from electron-scale magnetopause current sheet
Presentation Type
Talk
Presenter Format
Virtual Meeting Talk
Topic
Dayside Science
Start Date
10-5-2022 11:00 AM
Abstract
We present results from the reconstruction of a reconnecting electron-scale current sheet (ECS), reported by Burch and Phan (GRL, 2016), and three preceding ion-scale magnetic flux ropes (FRs) observed at the dayside magnetopause by the Magnetospheric Multiscale spacecraft on 8 December 2015. Based on the fact that the three southward-moving FRs were observed on the southern (downstream) side of the ECS, Dong et al. (GRL, 2017) suggested that they formed through secondary magnetic reconnection in the ECS. Magnetic fields recovered from both the electron-MHD (Hasegawa et al., JGR, 2021) and polynomial reconstruction methods (Denton et al., JGR, 2020) show that an ion-scale flux rope existed in the ECS with a significant core (guide) field. The Grad-Shafranov reconstruction applied to the three FRs suggests that they had axial orientations similar to that of the ion-scale FR in the ECS. These results support the suggestion by Dong et al. that ion-scale flux ropes can be generated through secondary magnetic reconnection or the tearing instability in ECS, rather than multiple reconnection at spatially separated locations. We discuss possible differences in the generation mechanism between ion-scale FRs, typical MHD-scale flux transfer events (FTEs), and a class of FTEs sandwiched between oppositely directed reconnection ion jets, all encountered at the magnetopause.
Evidence for ion-scale magnetic flux ropes generated from electron-scale magnetopause current sheet
We present results from the reconstruction of a reconnecting electron-scale current sheet (ECS), reported by Burch and Phan (GRL, 2016), and three preceding ion-scale magnetic flux ropes (FRs) observed at the dayside magnetopause by the Magnetospheric Multiscale spacecraft on 8 December 2015. Based on the fact that the three southward-moving FRs were observed on the southern (downstream) side of the ECS, Dong et al. (GRL, 2017) suggested that they formed through secondary magnetic reconnection in the ECS. Magnetic fields recovered from both the electron-MHD (Hasegawa et al., JGR, 2021) and polynomial reconstruction methods (Denton et al., JGR, 2020) show that an ion-scale flux rope existed in the ECS with a significant core (guide) field. The Grad-Shafranov reconstruction applied to the three FRs suggests that they had axial orientations similar to that of the ion-scale FR in the ECS. These results support the suggestion by Dong et al. that ion-scale flux ropes can be generated through secondary magnetic reconnection or the tearing instability in ECS, rather than multiple reconnection at spatially separated locations. We discuss possible differences in the generation mechanism between ion-scale FRs, typical MHD-scale flux transfer events (FTEs), and a class of FTEs sandwiched between oppositely directed reconnection ion jets, all encountered at the magnetopause.
