Characterization of High-m Poloidal ULF Wave signatures in GPS TEC Data
Abstract
GPS Total Electron Content (TEC) measurements have been used to investigate high-m poloidal ultra-low frequency (ULF) waves observed during the recovery phase of a geomagnetic storm. ULF signals in GPS TEC data show high coherence and significant common power in the Wavelet Coherence (WTC) and Cross Wavelet Transform (XWT) analyses of the radial magnetic field component (Br) data from the GOES-15 satellite. WTC and XWT results from GOES-15 and the TEC measurements from the GPS receiver close to the footprint of GOES-15 during Jan 24 to 26, 2016 are used to derive the ULF wave spatial distribution and temporal variation. The results show that poloidal mode ULF wave signatures in the GPS TEC data have a similar temporal and frequency variations with GOES-15 observations. GPS phase sigma and S4 indices suggest that the observed poloidal ULF waves had little contribution to ionospheric scintillation. Narrow band ULF wave signatures are identified in the TEC data from 13 GPS receivers on Jan 25, 2016. The results show that the high-m poloidal waves in the ionosphere during this event were mainly distributed on the dayside and post dusk sector from ~60 to ~75 degrees in magnetic latitude. The ULF wave power was strongest around dusk in magnetic local times. This is the first time that the 2D spatial structures and time evolution of high-m poloidal waves are revealed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMSM010..06Z
- Keywords:
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- 2772 Plasma waves and instabilities;
- MAGNETOSPHERIC PHYSICS;
- 2774 Radiation belts;
- MAGNETOSPHERIC PHYSICS;
- 2784 Solar wind/magnetosphere interactions;
- MAGNETOSPHERIC PHYSICS;
- 7867 Wave/particle interactions;
- SPACE PLASMA PHYSICS