Simultaneous Pi2 pulsation detected by CSES-01, Swarm, RBSP and Arase satellites

Area of Science:

• Space Physics
• Magnetospheric Physics
• Ionospheric Physics

Background:

• Pi2 magnetic pulsations are transient geomagnetic variations originating from the magnetosphere.
• Understanding their propagation is crucial for space weather forecasting.
• Previous studies often lacked multi-point, multi-mission observations.

Purpose of the Study:

• To present the first simultaneous multi-point observations of Pi2 magnetic pulsations using multiple spacecraft.
• To analyze the compressional and horizontal magnetic field components during a Pi2 event.
• To investigate the propagation characteristics and mechanisms of Pi2 pulsations.

Main Methods:

• Utilized data from CSES-01, Swarm (A, C), Van Allen Probes (RBSP-A, B), and Arase spacecraft.
• Analyzed compressional magnetic field components from satellites and horizontal components from the Kakioka (KAK) ground station.
• Applied wavelet and Hilbert-Huang transforms (HHT) for signal analysis.

Main Results:

• Observed strong coherence and wave-like structures in Pi2 pulsations across different altitudes and locations (dayside, nightside, dusk sector).
• Identified characteristics of radially trapped fast modes and cavity resonance.
• Found distinct propagation speeds and mechanisms for low- and high-frequency Pi2 pulsations.

Conclusions:

• The compressional components in the topside ionosphere and magnetosphere show similarities to ground-based observations.
• Pi2 pulsations exhibit waveguide-like propagation from the nightside magnetosphere sunward.
• The study confirms the complex nature and propagation of Pi2 pulsations using unprecedented multi-mission data.