Expansion of equatorial irregularities to mid-latitudes during the solar cycle 24.

Abstract:

The UNAVCO Global Positioning System (GPS) network with a 1-second data-rate is utilized to construct 2-D maps of ionospheric irregularities over the Central and North America. Provided carrier to noise ratio (CNR) is used to estimate GPS scintillation. A survey through 8 years of data between 2012 and 2019 reveals eight profound events of GPS scintillation recorded at mid-latitudes. We define mid-latitudes as a region in the northern hemisphere with magnetic latitude (MLAT) 30 < MLAT < 60. We find the scintillation instances occurred during geomagnetic storms, with mean Dst=-125nT, and Kp=6+. The scintillation-producing irregularities occurred throughout the sensor coverage, spanning from California to Florida. The irregularities show no seasonal nor solar cycle dependence. Whereby the scintillation peaked in the pre-midnight sector, but during several events, the scintillation lasted until sunrise. The irregularities expanded poleward of 35 MLAT, on some occasions beyond 45 MLAT. The irregularities map to altitudes above 3500 km in the equatorial plane, reaching L > 2. During storms, these heights are in the vicinity of the plasmapause and the ring current. Vicinity of the two electrodynamic features could alter the magnetosphere-ionosphere coupling in the sub-auroral region.