TY - Generic T1 - Statistical Study of the Magnetospheric Open-Closed Boundary (OCB) using ULF Wave Observations from Antarctic Ground Magnetometers As Compared to the Tsyganenko Model T2 - HamSCI Workshop 2024 Y1 - 2024 A1 - Rachel M. Frissell A1 - Hyomin Kim A1 - Andrew Gerrard A1 - Nathaniel A. Frissell AB -

We present a statistical study using ground magnetometer data which are located over extensive latitudes from subauroral to the deep polar cap region. These include the Antarctic Automated Geophysical Observatories (AGOs), McMurdo Station (MCM), and South Pole Station (SPA), to characterize open-closed boundary (OCB) behavior during geomagnetically quiet times. Knowledge of the location and dynamics of the magnetic field line OCB provides insight to space physics processes such as substorms, particle precipitation events, and magnetospheric configuration. Prior studies have shown that determination of the OCB location can be made by examining the ULF wave power in data from a latitudinal chain of ground-based magnetometers extending from the auroral zone into the deep polar cap.

JF - HamSCI Workshop 2024 PB - HamSCI CY - Cleveland, OH ER - TY - Generic T1 - Geomagnetic Indices and The Ring Current T2 - HamSCI Workshop 2022 Y1 - 2022 A1 - Matthew Cooper A1 - Andrew Gerrard AB -

Since the Space Age, the study of the near Earth space environment has become of great importance due to the advent of electrical systems, radio communications, and satellites which are directly affected by the state of the space environment around the Earth.  The study of the ‘weather’ of this space environment comes in many shapes and forms but has mostly centered around the analysis and prediction of disturbances in the environment. These disturbances have been dubbed ‘geomagnetic storms’, and their effects can range from inconsequential  to, in the most severe cases, society altering.  Several features of this space environment create changes at the ground level as they vary which can be measured and assigned values.  In this poster we focus on three such values: Kp, F10.7, and Sym-H/Dst.  The Sym-H/Dst index is of particular interest as it relates to one of the more prominent subsystems of the Earth’s geospace environment, namely the ring current.

JF - HamSCI Workshop 2022 PB - HamSCI CY - Huntsville, AL ER - TY - Generic T1 - Plasma Bubble and Blob Events in the F-region Ionosphere T2 - HamSCI Workshop 2021 Y1 - 2021 A1 - Sovit Khadka A1 - Cesar Valladares A1 - Andrew Gerrard AB -

The equatorial plasma bubbles (EPBs) and plasma blobs (enhancements) are, in general, the nighttime phenomena of ionospheric plasma irregularities in the F-region ionosphere. This study presents plasma bubble and blob events identified from the SWARM satellite constellation when it flies above the American continent. We have also simultaneously examined the behavior of total electron content (TEC), its depletions, and enhancements in the equatorial/low/mid-latitude F-region ionosphere detected from ground-based Global Positioning System (GPS) receivers in the American sector. The in situ observations of bubble and blob events are concurrently supported by GPS-TEC measurement from the ground. Additionally, the coordinated ground- and satellite-based observations indicate that the ground-based data show the variability of the background ionosphere prior, during, and later than the development time of the EPBs as seen by the SWARM. For this limited analysis, the plasma blob events are mostly seen at/nearby mid-latitude regions. Finally, we discuss the possible mechanism of the generation, evolution, and relationship between EPBs and plasma blobs in the F-region ionosphere.

JF - HamSCI Workshop 2021 PB - HamSCI CY - Scranton, PA (Virtual) UR - https://hamsci2021-uscranton.ipostersessions.com/?s=51-F0-AC-9D-0C-7E-D9-A3-FC-F1-2E-13-F2-6E-34-90 ER - TY - CONF T1 - Neutral Winds in the Equatorial Thermosphere as Measured With the SOFDI Instrument (ePoster) T2 - HamSCI Workshop 2020 Y1 - 2020 A1 - Sovit Khadka A1 - Andrew Gerrard A1 - John Meriwether AB -

The Second‐generation, Optimized, Fabry‐Perot Doppler Imager (SOFDI), a triple‐etalon Fabry‐Perot interferometer, is designed to measure both nighttime and daytime thermospheric winds from OI 630‐nm emission. These continual 24‐hour observations of thermospheric winds made with SOFDI under the geomagnetic equator at Huancayo, Peru, during northern summer, provide a unique data set. Results obtained from these data set are compared to the equatorial ionization anomaly (EIA) derived from  total electron content (TEC) and Jicamarca incoherent scatter radar (ISR) measurements of the pre‐reversal enhancement (PRE). We investigate the dynamics of the EIA asymmetry in response to measured thermospheric winds. A direct relationship between the afternoon winds and the magnitude of the PRE is also reported. The large variability of winds is observed in the afternoon which is likely caused by synoptic tidal activity modulating gravity waves. Also, a comparison between the measured neutral winds to that obtained from Horizontal Wind Model 14 is demonstrated. These results confirm the role that the thermospheric winds play in modulating equatorial dynamics and further demonstrate the need for both zonal and meridional components of the wind flow.

JF - HamSCI Workshop 2020 PB - HamSCI CY - Scranton, PA ER -