Magnetopause Reconnection as Influenced by the Dipole Tilt Under Southward IMF Conditions: Hybrid Simulation and MMS Observation

• Published in: Journal of geophysical research. Space physics 2020-09, Vol.125 (9), p.n/a
• Main Authors: Guo, Zhifang, Lin, Yu, Wang, Xueyi, Vines, Sarah K., Lee, S. H., Chen, Yuxi
• Format: Article
• Language: English
• Subjects: Dipoles; Environment models; Equator; Geomagnetic field; Geomagnetism; Interplanetary magnetic field; Ion velocity; Magnetic fields; Magnetic flux; Magnetic properties; Magnetopause; Magnetopause reconnection; Magnetosheath; Magnetospheres; Northern Hemisphere; Plasma jets; Power spectra; Simulation
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1029/2020JA027795

Using a three‐dimensional (3‐D) global‐scale hybrid code, the Magnetospheric Multiscale (MMS) reconnection event around 02:13 UT on 18 November 2015, highlighted in the Geospace Environment Modeling (GEM) Dayside Kinetic Challenge, is simulated, in which the interplanetary magnetic field (IMF) points southward and the geomagnetic field has a −27° dipole tilt angle. Strong southward plasma jets are found near the magnetopause as a result of the dayside reconnection. Our results indicate that the subsolar magnetopause reconnection X line shifts from the subsolar point toward the Northern Hemisphere due to the effect of the tilted geomagnetic dipole angle, consistent with the MMS observation. Subsequently, the reconnection X lines or sites and reconnection flux ropes above the equator propagate northward along the magnetopause. The formation and global distribution of the X lines and the structure of the magnetopause reconnection are investigated in detail with the simulation. Mirror mode waves are also found in the middle of the magnetosheath downstream of the quasi‐perpendicular shock where the plasma properties are consistent with the mirror instability condition. As a special outcome of the GEM challenge event, the spatial and temporal variations in reconnection, the electromagnetic power spectra, and the associated D‐shaped ion velocity distributions in the simulated reconnection event are compared with the MMS observation. Key Points Subsolar magnetopause X lines shift toward the Northern Hemisphere due to the effect of the negative tilted geomagnetic dipole angle The hybrid simulation magnetic fields and plasma date match MMS3 observations well during the magnetopause crossing Mirror mode waves appear in the middle of the magnetosheath downstream of the quasi‐perpendicular shock