  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.
