NSF Award
2431664
High-frequency (HF, 3–30 MHz) radio waves play a significant role in long-distance communications. They have applications in short-wave international broadcasting and communications by aircraft, military operations, and amateur radio operators and are useful during emergency situations. HF radio wave communication is possible through wave reflection and refraction in the ionosphere, which is part of the upper atmosphere at 100-2000 km altitude. The project aims at investigating the effect of the ionospheric density fluctuations on the propagation of HF radio waves, and the results of this project are expected to improve understanding of ground HF communications. This research will provide opportunities to under-represented communities in STEM areas at a minority serving institution. The effort is being led by a woman scientist and involves several early career scientists. The project integrates research into the Ham Radio Science Citizen Investigation program to investigate the effects of disturbances on HF communication. The results will be widely distributed and of significant interest to various groups, including amateur radio enthusiasts, emergency services, airlines, maritime organizations, and defense users.<br/><br/>The research work will investigate the effect of ionospheric density fluctuations on HF wave propagation. Since solar and geomagnetic activities significantly influence the ionosphere, HF radio communications are also sensitive to space weather. The project will address three scientific questions: (a) How are ground HF communications affected by different solar and geomagnetic activities? (b) How do small-scale density irregularities appear in various space weather conditions? (c) How do HF waves propagate through the irregular density profile?; and finally (d) How does space weather affect small-scale density irregularities and ground HF communications?. To achieve these goals, researchers will utilize satellite, HF amateur radio communication data sets, and will perform full-wave simulations using advanced finite element method (FEM) code, Petra-M by adopting a realistic density fluctuation profile. By comparing the predicted wave properties from the Petra-M code with the observed HF communications, it will be possible to evaluate how well the model simulates real-life conditions while providing new insight into how the HF radio waves propagate through ionospheric irregularities.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
