The Relationship Between Dynamic Changes in the Ionosphere-Thermosphere and Impacts on LF/HF Propagation: An Experimental Design for Future Eclipses

The 2017 eclipse was one of the most well instrumented and well studied events in recent history. In addition to the large amount of scientific instrumentation, analysis and publications there was a great deal of interest by the amateur scientific community as well as the public at large. Scientifically, a large number of papers have been published that make use of the eclipse as a diagnostic into the nature of the ionosphere- thermosphere coupling and the dynamics that occurred during the passage of the eclipse.

However, somewhat less attention has been paid to understanding how the propagation parameters dynamically change during the passage of an eclipse. The passage of an eclipse will, of course, cause a change in the overall ionospheric plasma density. However, the dynamical changes in the thermosphere and ionosphere can also cause severe horizontal and vertical gradients in the ionosphere that can significantly impact propagation. In addition, the variations in the thermosphere and ionosphere can initiate and launch traveling ionospheric disturbances (TIDS). All of these dynamical variations are likely to be frequency dependent, altitude dependent, and dependent on the propagation path taken.

This presentation has two parts. The first part of the presentation provides a description of the types of LF/HF data taken during the 2017 eclipse and a brief analysis focused on what the observations can tell about the propagation conditions and how they vary during the eclipse. Results from the digisonde located in Idaho, SuperDARN HF observations and a data collection on the west coast of HF CODARS and LF observations from, California and WWV in Fort Collins will be presented.

The second part of the presentation discusses possible instrumentation deployment designs for future eclipses, focusing on the variation in LF/HF propagation during an eclipse. Different design options will be considered, under the assumption of having ideal conditions (limitless funding, frequency allocations, etc.), that would optimize the diversity of observations and provide the most complete sets of observations to study the relationship between changes in the ionosphere-thermosphere and propagation.