Ionospheric Dynamics: Radio Investigations During the 2024 Total Solar Eclipse Maris Usis, Laura Schwartz, Adam Goodman, Department of Electrical Engineering; Dr. David Kazdan, John Gibbons, Department of Electrical Engineering (CWRU) The 8 April 2024 eclipse is an extraordinary natural experiment in ionospheric physics. The three defined layers of the ionosphere (D, E, and F) will have their solar illumination changed in a sharp-edged, absolutely defined and predictable way. Our work examines that structural change using measurements of shortwave radio propagation (reflection) time and received signal strength along the line of the eclipse path. The science questions we seek to answer concerns recombination time of small-molecule ions as they are irradiated by the sun’s extreme-ultraviolet (EUV) and soft X-ray photons. This is difficult to study, as the ionosphere is too high for aircraft sampling and too low for satellites. Ionospheric sounding generally involves lower frequencies than are available from CHU’s HF transmissions. Other projects have examined high-frequency radio propagation across eclipse paths, especially using National Institute of Standards and Technology radio station WWV, and shown promising results. Ours exploits the unique geography of this particular eclipse and its path alignment with the Research Council of Canada shortwave transmitter CHU in Ottawa, Ontario. We have custom-designed shortwave radio packages with automated data collection and uploading. We recruited volunteer radio operators among university and high school radio clubs and others. Receiving stations are distributed across Canada, the United States, and Mexico but are concentrated along the eclipse path. The stations’ reception of CHU’s signals over the two week period centered on the eclipse day will be analyzed for changes as the moon’s shadow passes over the radio signal “skip” points. The work promises to provide new and interesting methods of predicting space weather events that are significant to national power grids, communications systems, and radionavigation systems. First-light data are presented here and further data reduction will be performed over the next academic year. Project Mentors: Dr. David Kazdan, Electrical Engineering, CWRU; John Gibbons, Electrical Engineering, CWRU Faculty Sponsor: Professor Christian Zorman, School of Engineering, CWRU