Scintillation and irregularities from the nightside part of a Sun‐aligned polar cap arc

Abstract

In this paper we study the presence of irregularities and scintillation in relation to the nightside part of a long‐lived, Sun‐aligned transpolar arc on 15 January 2015. The arc was observed in DMSP UV and particle data and lasted at least 3 h between 1700 and 2000 UT. The arc was more intense than the main oval during this time. From all‐sky imagers on Svalbard we were able to study the evolution of the arc, which drifted slowly westward toward the dusk cell. The intensity of the arc as observed from ground was 10–17 kR in 557.7 nm and 2–3.5 kR in 630.0 nm, i.e., significant emissions in both green and red emission lines. We have used high‐resolution raw data from global navigation satellite systems (GNSS) receivers and backscatter from Super Dual Auroral Radar Network (SuperDARN) radars to study irregularities and scintillation in relation to the polar cap arc. Even though the literature has suggested that polar cap arcs are potential sources for irregularities, our results indicate only very weak irregularities. This may be due to the background density in the northward IMF polar cap being too low for significant irregularities to be created.

Aurora in the Polar Cap: A Review

“…Jayachandran et al (2017) detected amplitude and phase scintillations, which are rapid random fluctuations of the amplitude and phase of trans-ionospheric radio signals, in close association with polar cap arcs, indicating the occurrence of kilometer scale electron density fluctuations, i.e., irregularities, in the ionosphere. On the other hand, van der Meeren et al (2016) used DMSP SSUSI images to study the presence of irregularities in the ionosphere and scintillation caused by polar cap arcs. They used multiple other data sources and concluded, in this case, that the polar cap arc was only a weak source of irregularity.…”

GPS Scintillations and Losses of Signal Lock at High Latitudes During the 2015 St. Patrick's Day Storm

“…At high latitudes, the scintillation effect on Global Positioning System (GPS) signals has been associated with phenomena like storm-enhanced density, polar cap patches, and auroral precipitation (Alfonsi et al, 2011;De Franceschi et al, 2008;Jin et al, 2014Jin et al, , 2015Li et al, 2010;Mitchell et al, 2005;Moen et al, 2013;Oksavik et al, 2015;Prikryl et al, 2010Prikryl et al, , 2011Prikryl et al, , 2013Smith et al, 2008;Spogli et al, 2009;van der Meeren et al, 2014van der Meeren et al, , 2015van der Meeren et al, , 2016. The strongest GPS phase scintillations are associated with auroral blobs that are formed when polar cap patches enter the nightside auroral region (Jin et al, 2014;van der Meeren et al, 2015).…”

Multi-instrument observations of large-scale atmospheric gravity waves/traveling ionospheric disturbances associated with enhanced auroral activity over Svalbard

“…Maps showing: (a) locations of GNSS receivers (blue squares), FPI (green cross), allsky camera (black plus sign) and magnetometers (red circle) used in this study;(b) ionospheric pierce points for GPS PRNs 3, 6 and 11.that the University of Bergen installed in Svalbard in 2013. Data from these receivers have been used in the past to study the poleward edge of the nightside auroral oval (van der Meeren et al, 2015), dayside auroral forms(Oksavik et al, 2015), and polar cap arcs(van der Meeren et al, 2016).Figure 1(b)shows projections of ionospheric pierce points, calculated assuming the ionosphere is a thin shell sitting at 300 km, for satellites with elevation angles greater than 30 • to illustrate our TEC data spatial coverage.…”