5:15 PM - 6:45 PM
[PEM10-P07] Spatial Analysis of Pi2 Pulsations to Explore the Initial Phase of Substorm M-I Global Coupling System
Keywords:Pi2, M-I coupling system, ICA
Pi2 pulsations, impulsive hydromagnetic oscillations with a period of 40–150s, occur globally at the onset of magnetospheric substorm expansion phase. Pi2 serves as a useful natural signal for understanding the propagation of magnetic field variations in the magnetosphere and ionosphere, leading to research on its generation and propagation mechanisms. Therefore, analyzing Pi2 is crucial for understanding the dynamics of the magnetosphere-ionosphere (M-I) coupling system at the onset of substorms.
Previous studies have proposed various hypotheses on the Pi2 propagation mechanisms such as transient Alfvén and fast modes, field line resonance and cavity-type resonance. However, there are few globally analyzing Pi2 using ground magnetic field observation points and investigating its spatio-temporal distribution characteristics, and propose a Pi2 propagation mechanisms. The goal of this study is to elucidate the global picture of the M-I coupling system at the onset of substorms by understanding the global spatiotemporal distribution characteristics of Pi2.
In this study, we use Independent Component Analysis (ICA) to analyze Pi2 pulsations. ICA allows for the extraction of components based on waveform independence (non-Gaussian) and simultaneous analysis of multivariate data. Therefore, ICA is an effective analysis method for simultaneously analyzing globally independent Pi2 and understanding its spatial distribution. This approach is applied to data from 210MM chain and North-South America chain of the MAGDAS/CPMN network, focusing on quiet magnetospheric conditions and isolated substorms.
In particular, the analysis of the D component of Pi2 on the night side reveals a phase reversal on the magnetic equator and an increase in amplitude at high latitudes. These results suggest the possibility that oscillatory plasma flow causes east-west oscillation of the magnetic field lines, which propagates along the magnetic field lines and is observed on the ground as the D component of Pi2. Detailed results and discussion will be presented in this presentation.
Previous studies have proposed various hypotheses on the Pi2 propagation mechanisms such as transient Alfvén and fast modes, field line resonance and cavity-type resonance. However, there are few globally analyzing Pi2 using ground magnetic field observation points and investigating its spatio-temporal distribution characteristics, and propose a Pi2 propagation mechanisms. The goal of this study is to elucidate the global picture of the M-I coupling system at the onset of substorms by understanding the global spatiotemporal distribution characteristics of Pi2.
In this study, we use Independent Component Analysis (ICA) to analyze Pi2 pulsations. ICA allows for the extraction of components based on waveform independence (non-Gaussian) and simultaneous analysis of multivariate data. Therefore, ICA is an effective analysis method for simultaneously analyzing globally independent Pi2 and understanding its spatial distribution. This approach is applied to data from 210MM chain and North-South America chain of the MAGDAS/CPMN network, focusing on quiet magnetospheric conditions and isolated substorms.
In particular, the analysis of the D component of Pi2 on the night side reveals a phase reversal on the magnetic equator and an increase in amplitude at high latitudes. These results suggest the possibility that oscillatory plasma flow causes east-west oscillation of the magnetic field lines, which propagates along the magnetic field lines and is observed on the ground as the D component of Pi2. Detailed results and discussion will be presented in this presentation.