GPS scintillation and irregularities at the front of an ionization tongue in the nightside polar ionosphere

In this paper we study a tongue of ionization (TOI) on 31 October 2011 which stretched across
the polar cap from the Canadian dayside sector to Svalbard in the nightside ionosphere. The TOI front
arrived over Svalbard around 1930 UT. We have investigated GPS scintillation and irregularities in relation to
this TOI front. This is the first study presenting such detailed multi-instrument data of scintillation and
irregularities in relation to a TOI front. Combining data from an all-sky imager, the European Incoherent
Scatter Svalbard Radar, the Super Dual Auroral Radar Network Hankasalmi radar, and three GPS scintillation
and total electron content (TEC) monitors in Longyearbyen and Ny-Ålesund, we observe bursts of phase
scintillation and no amplitude scintillation in relation to the
leading gradient of the TOI. Spectrograms of
50Hz phase measurements show highly localized and variable structuring of the TOI leading gradient, with
no structuring or scintillation within the TOI or ahead of the TOI.