Investigating the Occurrence of Magnetic Reconnection at Jupiter's Dawn Magnetopause During the Juno Era

Abstract

In this study, observations from the Jovian auroral distributions experiment, Jupiter energetic particle detector instrument, and Magnetic field investigation instruments on Juno are used to identify signatures of magnetic reconnection at Jupiter's dawn magnetopause and relate these signatures to the local plasma environment. Magnetopause crossings occurred between 73–114 Jovian radii and 4.3–6.2 magnetic local time at low latitudes. Reconnection signatures include plasma energization and ion velocity enhancements resembling reconnection jets. We test for diamagnetic suppression which considers the magnetic shear and plasma beta (β) before and after a magnetopause crossing. Findings show that a large majority of these dawn magnetopause crossings at Jupiter have a low likelihood for local magnetic reconnection (are diamagnetically suppressed) because of high delta β values and/or low magnetic shear angles across the magnetopause boundary. These crossings exhibit no evidence of local reconnection while crossings that are not diamagnetically suppressed show multiple signatures of reconnection, adhering to the Swisdak relation.

Prediction of Axial Asymmetry in Jovian Magnetopause Reconnection

“…Axial asymmetry in the Jovian magnetopause reconnection is related to significant dawn‐dusk asymmetric and helical configuration of magnetospheric magnetic fields driven by Jovian fast rotation. The simulated asymmetry in Jovian magnetopause reconnection is consistent with the low reconnection probability at the dawnside magnetopause in the Juno data (Montgomery et al., 2022). Juno has proceeded its orbit to the high‐altitude cusp (Bolton et al., 2017), so the new picture proposed in this study could be directly examined in the near future.…”

Dipolarization Fronts in the Jovian Magnetotail: Statistical Survey of Ion Intensity Variations Using Juno Observations

“…(2017) and Montgomery et al. (2022). We exclude the significant B θ deflections from our study because they are located at the magnetopause or in the magnetosheath (see selection criterion #3).…”

“…3. Events which are identified during the time when Juno is located in the magnetosheath or close to the magnetopause or bow shock crossing (mostly events during PJ1 and PJ2 when Juno was located between 05:30 and 06:00 LT) according to the lists of Hospodarsky et al (2017), Ranquist et al (2019), andMontgomery et al (2022) are excluded in order to focus only on internal magnetotail dynamics. 4.…”

“…(2019), and Montgomery et al. (2022) are excluded in order to focus only on internal magnetotail dynamics. We require that B θ does not have a high level of variability in a time interval of 15 min before t min . Therefore, we calculate the standard deviation σ of B θ in this interval and choose only events with σ < 2.5 nT.…”

“…(2019), and Montgomery et al. (2022) are excluded in order to focus only on internal magnetotail dynamics.…”