Ionospheric Response to the Solar Eclipse of 21 August 2017 in Millstone Hill (42N) Observations

Abstract

Abstract This study examines the ionospheric changes associated with the solar eclipse of 21 August 2017. The effects associated with the passage of the eclipse shadow were observed more than 1,000 km away from the totality at midlatitudes using the Millstone Hill incoherent scatter radar and digisonde. There was a 30–40% decrease in electron density, a 100‐ to 220‐K decrease in electron temperature, and a 50‐ to 140‐K decrease in ion temperature. Surprisingly, the greatest decrease in electron density occurred above 200 km. The most unexpected effect was a large 20‐ to 40‐m/s upward vertical drift observed in the topside ionosphere right after the local maximum obscuration. We suggest that this drift led to a posteclipse increase in the topside electron density.