TY - CONF T1 - Observations and Modeling Studies of the Effects of the 2017 Solar Eclipse on SuperDARN HF Propagation T2 - HamSCI Workshop 2020 Y1 - 2020 A1 - M. Moses A1 - L. Kordella A1 - G. D. Earle A1 - D. Drob A1 - J. Huba A1 - J. M. Ruohoniemi AB -

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’s campaign and/or similar ionospheric studies for the next eclipse over the United States in 2024.

JF - HamSCI Workshop 2020 PB - HamSCI CY - Scranton, PA ER - TY - CONF T1 - On the use of solar eclipses to study the ionosphere T2 - 15th International Ionospheric Effects Symposium IES2017 Y1 - 2017 A1 - W. Liles A1 - C. Mitchell A1 - M. Cohen A1 - G. Earle A1 - N. Frissell A1 - K. Kirby-Patel A1 - L. Lukes A1 - E. Miller A1 - M. Moses A1 - J. Nelson A1 - J. Rockway AB -

Exploring the effects of solar eclipses on radio wave propagation has been an active area of research since the first experiments conducted in 1912. In the first few decades of ionospheric physics, researchers started to explore the natural laboratory of the upper atmosphere. Solar eclipses offered a rare opportunity to undertake an active experiment. The results stimulated much scientific discussion.
Early users of radio noticed that propagation was different during night and day. A solar eclipse provided the opportunity to study this day/night effect with much sharper boundaries than at sunrise and sunset, when gradual changes occur along with temperature changes in the atmosphere and variations in the sun angle.
Plots of amplitude time series were hypothesized to indicate the recombination rates and re- ionization rates of the ionosphere during and after the eclipse, though not all time-amplitude plots showed the same curve shapes. A few studies used multiple receivers paired with one transmitter for one eclipse, with a 5:1 ratio as the upper bound. In these cases, the signal amplitude plots generated for data received from the five receive sites for one transmitter varied greatly in shape.

JF - 15th International Ionospheric Effects Symposium IES2017 CY - Alexandria, VA ER -