An investigation of the nature of a Pc5 pulsation event using SuperDARN and magnetometer data

Abstract

Pc5 pulsations are global magnetohydrodynamic events in the magnetosphere. We employed an Automated Pulsation Finder program to identify significant Pc5 pulsation events in SuperDARN radar data. The event presented here was visible in the Goose Bay, Saskatoon and Þykkvibaer high-frequency radars, located in the northern polar region. These observations were coordinated with magnetometers within their field of view. These two instrument types – radars and magnetometers – complement each other. These observations represent a significant fraction of the globe in longitude. Pulsation studies of this nature are rare in the literature. Combining these two instrument types, we investigated the nature of the pulsation and determined its qualitative polarisation characteristics. A complex demodulation technique was employed to determine amplitude and phase relationships between field components observed by the radars and magnetometers, which, in turn, afforded resolution of other characteristics of pulsations, such as wave number and phase velocity. The results are discussed in the context of the magnetohydrodynamic theory of magnetic pulsations, speculating on its generation mechanism. Investigation of this mechanism will be the subject of a future publication.

Evolving Phase Propagation in an Intermediate‐m ULF Wave Driven by Substorm‐Injected Particles

“…Due to ionospheric screening, the attenuation factor has to be small in order for the waves to be detected on the ground by magnetometers. Whilst ULF waves with a high m number have been simultaneously detected in the ionosphere by radar and in ground magnetometer data (e.g., Yeoman et al., 2012; Mtumela et al., 2015), such multi‐instrument observations of intermediate‐ m and high‐ m waves are sparse. The same particle energy predicted for the 0.8 mHz wave observed by the radar is applicable for the magnetometer data, clearly indicating that the same wave activity was observed simultaneously in the radar and magnetometer data.…”

“…For example, Mtumela et al. (2015) note that ground magnetometers and HF radars are synergistic instrument types for studying ULF waves.…”

“…Journal of Geophysical Research: Space Physics 10.1029/2023JA031654 structure of ULF waves, even though they are rare. For example, Mtumela et al (2015) note that ground magnetometers and HF radars are synergistic instrument types for studying ULF waves.…”

Large-scale coordinated observations of Pc5 pulsation events

“…Recently, (hereafter Paper 1; Mtumela et al, 2015) have reported a detailed case study of a magnetospheric field line resonance with a frequency in the Pc5 range using radars from SuperDARN (Super Dual Auroral Radar Network; Greenwald et al, 1995;Chisham et al, 2007) and the CARISMA (Canadian Array for Realtime Investigations of Magnetic Activity; Mann et al, 2008), Greenland (DTU Space, 2015), and IMAGE (International Monitor for Auroral Geomagnetic Effects; Tanskanen, 2009) magnetometer arrays. The global coverage of this event was substantially greater than in previous such studies (Fenrich et al, 1995;Ziesolleck et al, 1998).…”