SM006-0012
Ground Magnetometer ULF Wave Observations at the Convection Reversal Boundary During Sustained Periods of Dominant IMF By

Monday, 7 December 2020
Poster
Shane Coyle, Virginia Polytechnic Institute and State University, Blacksburg, United States, C. Robert Clauer, National Institute of Aerospace, Hampton, VA, United States; Virginia Polytechnic Institute and State University, Blacksburg, VA, United States and Michael Hartinger, Space Science Institute Boulder, Boulder, CO, United States; Virginia Polytechnic Institute and State University, Bradley Department of Electrical and Computer Engineering, Blacksburg, VA, United States
Abstract:
It has been suggested that convection shear resulting from periods of dominant interplanetary magnetic field (IMF) By is responsible for the generation of Kelvin-Hemholtz instabilities (KHIs) in the noon and pre-noon sectors that ultimately provides a source of energy for closed field line resonances (FLRs) within the magnetosphere. Several case studies presented by Clauer et. al. have identified ultra-low frequency (ULF) wave signatures consistent with FLRs in ground magnetometers near the convection reversal boundary as placed by incoherent scatter radar observations from Søndre Strømfjord. This study expands on past work related to the generation of FLRs by KHI during periods of predominantly East-West IMF orientation by examining ground magnetometer data in both hemispheres during several hundred events over the course of 4 years. OMNI solar wind data is analyzed for periods where the solar wind magnetic field vector points along the GSM Y-axis and is of significant magnitude for periods lasting greater than 30 minutes. We find results initially consistent with Clauer et. al., and provide new insights into periods where the IMF vector points west instead of east as previously examined.
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