Ionospheric and geomagnetic response to the total solar eclipse on 21 August 2017

TL;DR

This study analyzes the ionospheric and geomagnetic responses to the 2017 solar eclipse using GNSS and geomagnetic data, revealing the timing and magnitude of effects and validating models that link ionospheric depletion to magnetic field variations.

Contribution

It provides a detailed quantitative analysis of ionospheric and geomagnetic reactions to the eclipse, and validates models linking ionospheric depletion to magnetic field changes.

Findings

VTEC depletion correlates with eclipse timing

Model predictions match observed magnetic field variations

Time delay of maximum depletion characterized

Abstract

Solar eclipses provide an excellent opportunity to study the effects of a sudden localized change in photoionization flux in the Earth's ionosphere and its consequent repercussion in the Geomagnetic field. We have focused on a subset of the data available from the North American 2017 eclipse in order to study VTEC measurements from GNSS data and geomagnetic field estimations from INTERMAGNET observatories near the eclipse path. Our simultaneous analysis of both datasets allowed us to quantify the ionosphere and magnetic field reaction to the eclipse event with which allowed us to compare how differently these take place in time. We found that studying the behaviour of VTEC differences with respect to reference values provides better insight of the actual eclipse effect and were able to characterize the dependence of parameters such as time delay of maximum depletion and recovery phase. We were also able to test models that link the ionospheric variations in a quantitative manner. Total electron content depletion measured from GNSS were fed into an approximation of Ashour-Chapman model at the locations of geomagnetic observatories and its predictions match the behaviour of magnetic field components in time and magnitude strikingly accurately.