@proceedings {929, title = {HamSCI Solar Eclipse QSO Party (SEQP): Observations and Modeling on Ionospheric Effects}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

This study investigates the ionospheric changes during the solar eclipse of April 2024 using data from the HamSCI Solar Eclipse QSO Party (SEQP). SEQP collected radio communication data reported by ham radio operators and global automated receiving networks (e.g., WSPRNet, the Reverse Beacon Network, and PSKReporter). The datasets include radio communications at multiple frequencies in the high frequency (HF) and very high frequency (VHF) bands. Thousands of ham radio operators across the contiguous United States (CONUS) and around the globe contributed to the observations with unprecedented temporal, spatial, and spectral coverage. SEQP datasets are used to infer ionospheric state before, during, and after the solar eclipse. We use the ham radio datasets along with PHaRLAP raytrace modeling to infer the ionospheric response of the solar eclipse and also evaluate the outputs of the physics-based model SAMI3 for the eclipse ionosphere. Our findings suggest that the solar eclipse increased the range of radio communications at lower HF band (3.5, 7, 10 MHz), but decreased the longer range communications at higher HF band (21, 24, 28 MHz). Ham radio datasets from stations continually operated during the eclipse show an earlier opening of radio links between the US and Europe on the eclipse day. We are conducting modeling studies to understand the causes of changes in ham radio observations and to examine the potential combined effect of the sunset terminator and eclipse shadow during the later phase of the eclipse.

}, author = {Kuldeep Pandey and Gareth Perry and Nathaniel Frissell and Travis Atkinson and William Engelke and Joseph Huba and Mary Lou West and Philip Gladstone and Cameron Cushing and McKenzie Denton and Edward Efchak and Gary Mikitin and H. Ward Silver} } @proceedings {867, title = {PyLAP/PHaRLAP HF Ray Tracing and SAMI3: Integration and Refactoring}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

PyLAP is a high frequency (HF) ray tracing toolkit that is used to model radio wave propagation through the ionosphere. Currently PyLAP uses the empirical International Reference Ionosphere (IRI) model. In an effort to use PyLAP to observe more discrete structures in ionosphere that are otherwise unobservable with IRI, PyLAP is being Integrated with the Physics-based SAMI3 Model of the ionosphere. Along with this there will be an effort to refactor some of the current PyLAP codebase so that it is more readable and usable for anyone using the current system including both professional and citizen scientists.

}, author = {Devin Diehl and Rachel Boedicker and Joseph Huba and Nathaniel A. Frissell} } @proceedings {705, title = {Modeling the Ionosphere with SAMI3 (Invited Tutorial)}, year = {2023}, month = {03/2023}, publisher = {HamSCI}, address = {Scranton, PA}, abstract = {

SAMI3 (Sami3 is Also a Model of the Ionosphere) is a global, comprehensive model of the ionosphere/plasmasphere system. It is based on the SAMI2 model developed at the Naval Research Laboratory (Huba et al., 2000). SAMI3 models the plasma and chemical evolution of seven ion species (H, He, N, O, N, NO and O). The ion temperature equation is solved for three ion species (H, He and O) as well as the electron temperature equation. Ion inertia is included in the ion momentum equation for motion along the geomagnetic field. The neutral composition and temperature can be specified by empirical models (e.g, NRLMSISE00, HWM14) or by first-principle atmosphere models (e.g., TIEGCM, WACCM-X, HIAMCM). SAMI3 uses a nonorthogonal, nonuniform, fixed grid. The grid is designed to optimize the numerical mesh so that the spatial resolution decreases with increasing altitude. SAMI3 can use an untilted or tilted dipole model of earth{\textquoteright}s magnetic field, or an IGRF field model based on the Richmond apex model. A general overview of ionospheric physics and the SAMI3 model will be presented, as well as several applications of the code.

}, author = {Joseph Huba} }