Simultaneous Remote Observations of Intense Reconnection Effects by DMSP and MMS Spacecraft During a Storm Time...

Area of Science:

• Space Physics
• Magnetospheric Physics
• Plasma Physics

Background:

• Intense magnetic storms can trigger substorms and magnetotail reconnection.
• Simultaneous observations by multiple spacecraft are crucial for understanding these dynamic events.

Purpose of the Study:

• To analyze the signatures of a very intense magnetic reconnection event during a 2015 magnetic storm.
• To investigate the spatial and temporal evolution of the magnetotail boundary layer using high-resolution spacecraft data.

Main Methods:

• Utilized data from DMSP and Magnetospheric Multiscale (MMS) spacecraft during a geomagnetic storm on June 23, 2015.
• Analyzed simultaneous crossings of the reconnection separatrix layer by DMSP F18 and MMS.
• Examined energy dispersion of energetic ions and electrons, polar rain electrons, and magnetic field line convection.

Main Results:

• Observed consistent signatures of energy dispersion in earthward-traveling energetic ions and electrons at the separatrix.
• Detected energy-dispersed polar rain electrons with a high-energy cutoff.
• MMS recorded intense inward convection of magnetic field lines, providing high-resolution data of the electron boundary layer.

Conclusions:

• The magnetotail magnetic reconnection process was intrinsically impulsive.
• The active X-line was located relatively close to Earth, approximately at 16-18 Earth radii (R_E).
• Electron energy dispersion and pitch angle distribution provide insights into boundary layer evolution during reconnection.