@proceedings {940,
	title = {Effect of the equatorial plasma bubbles on amateur radio communication: Full-wave simulation Study},
	year = {2025},
	month = {03/2025},
	publisher = {HamSCI},
	address = {Newark, NJ},
	abstract = {<p>We present the impact of equatorial plasma bubbles (EPB) on high-frequency (HF) wave propagation, such as amateur (ham) radio communications, in the ionosphere. Ionospheric density irregularities occur over a wide range of latitudes from the equator to the polar region and local times. Many numerical efforts have been made to study wave propagation in the ionosphere; however, several challenges arise in modeling the propagation of HF waves. For example, the wavelength of radio waves in the ionosphere is much shorter than the ray path and the thickness of the ionosphere; thus, simulating these waves requires high-performance computing resources. This challenge is one reason why previous research has predominantly focused on ray tracing and analytical calculations. For such reasons, the properties of HF waves{\textemdash}such as reflection, refraction, scattering, and scintillation{\textemdash}are not fully understood in the context of density irregularities. This presentation introduces the state-of-the-art full-wave simulation code, Petra-M. \&nbsp;We then conduct numerical examinations of how the EPB affects HF wave propagation. We utilize density irregularity structures, such as EPBs, derived from other simulations as background ionospheric density structures. Due to the small-scale density fluctuations in the EPB, HF waves can reach higher altitudes with scattering and trapping in the density structure. Mode conversion from the incoming HF wave to the electrostatic waves, which are localized waves in the ionosphere, also occurs. Such effects can lead to failed wave detection at the receiver since the wave power reaches a broader area near the receiver due to scattering, and wave power can decrease because of the wave mode conversion.</p>
},
	author = {Eun-Hwa Kim and S. Shiraiwa and J. R. Johnson and J. Huba and K Hozumi and S. Wing and N. Bertelli}
}
@conference {383,
	title = {Observations and Modeling Studies of the Effects of the 2017 Solar Eclipse on SuperDARN HF Propagation},
	booktitle = {HamSCI Workshop 2020},
	year = {2020},
	month = {03/2020},
	publisher = {HamSCI},
	organization = {HamSCI},
	address = {Scranton, PA},
	abstract = {<p>The total solar eclipses offer a unique opportunity to study the dependence of the ionospheric density and morphology on incident solar radiation. Unique responses may be witnessed during eclipses, including changes in radio frequency (RF) propagation at high frequency (HF). Such changes in RF propagation were observed by the Super Dual Auroral Radar Network (SuperDARN) radars in Christmas Valley, Oregon and in Fort Hayes, Kansas during the 2017 solar eclipse. At each site, the westward looking radar observed an increase in slant range of the backscattered signal during the eclipse onset followed by a decrease after totality. In order to investigate the underlying processes governing the ionospheric response to the eclipse, we employed the HF propagation toolbox (PHaRLAP), created by Dr. Manuel Cervera, to simulate SuperDARN data for different models of the eclipsed ionosphere. By invoking different hypotheses and comparing simulated results to SuperDARN measurements we could study the underlying processes governing the ionosphere and improve our model of the F-Region responses to an eclipse. This method was used in three studies to: identify the cause of the increase in the distance radio waves traveled during the eclipse; evaluate different models of change in eclipse magnitude over time; and investigate the effect of the neutral wind velocity on the simulated eclipse data. This presentation will discuss observations made by SuperDARN during the 2017 eclipse, major results from our raytrace studies, and unanswered questions that may be useful to consider when planning HamSCI{\textquoteright}s campaign and/or similar ionospheric studies for the next eclipse over the United States in 2024.</p>
},
	author = {M. Moses and L. Kordella and G. D. Earle and D. Drob and J. Huba and J. M. Ruohoniemi}
}
