Characterizing the ionospheric current pattern response to southward and northward IMF turnings with dynamical SuperMAG correlation networks

TL;DR

This study uses dynamical correlation networks of ground magnetometers to analyze how the ionospheric currents respond to IMF turnings, revealing timing and spatial patterns linked to convection systems.

Contribution

It introduces a novel dynamical network approach to characterize ionospheric responses to IMF turnings using SuperMAG magnetometer data.

Findings

Regions with increased correlation align with convection system locations.

Response time from IMF turning to network change is approximately 8-10 minutes.

Dayside correlations precede nightside by 2-8 minutes.

Abstract

We characterize the response of the quiet time (no substorms or storms) large-scale ionospheric transient equivalent currents to north-south and south-north IMF turnings by using a dynamical network of ground-based magnetometers. Canonical correlation between all pairs of SuperMAG magnetometer stations in the Northern Hemisphere (magnetic latitude (MLAT) 50-82$^{\circ}$) is used to establish the extent of near-simultaneous magnetic response between regions of magnetic local time-MLAT. Parameters and maps that describe spatial-temporal correlation are used to characterize the system and its response to the turnings aggregated over several hundred events. We find that regions that experience large increases in correlation post turning coincide with typical locations of a two-cell convection system and are influenced by the interplanetary magnetic field $\mathit{B}_{y}$. The time between the turnings reaching the magnetopause and a network response is found to be $\sim$8-10 min and correlation in the dayside occurs 2-8 min before that in the nightside.