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.
Highlights
The geomagnetic field exhibits variations in timescales that range from fractions of seconds to millions of years
Some of them are internally generated and others are external, created in the ionosphere-magnetosphere system. Among these the regular daily variation of geomagnetic field during quiet time periods is a common feature of geomagnetic field measurements; the current system associated with the geomagnetic daily variation is typically termed the solar quiet (Sq) current system
In this work we propose to simultaneously study both ionospheric and geomagnetic response to the 2017 North America Solar Eclipse, combining information provided by GNSS measurements and quantifying its relation to observed geomagnetic perturbations
Summary
The geomagnetic field exhibits variations in timescales that range from fractions of seconds to millions of years. Cherniak and Zakharenkova, 2018; Dang et al, 2018; Goncharenko et al, 2018; Bullett and Mabie, 2018; Reinisch et al, 2018; Cnossen et al, 2019; Wang et al, 2019) The latter concludes that throughout the course of the moon’s shadow over a particular observation site, the disturbance winds at the site change direction and their effects on the electron densities of the F2 region vary. Hvozdara and Prigancova (2002) proposed a mathematical model based on the classical Ashour-Chapman model to explain the geomagnetic field components’ variation They quantify these in terms of the position of both the quasi-circular spot of the ionospheric conductivity decrease and the location of the geomagnetic observatory. In this work we propose to simultaneously study both ionospheric and geomagnetic response to the 2017 North America Solar Eclipse, combining information provided by GNSS measurements and quantifying its relation to observed geomagnetic perturbations
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