GNSS Scintillations in the Cusp, and the Role of Precipitating Particle Energy Fluxes

Abstract

Using a large data set of ground‐based GNSS scintillation observations coupled with in situ particle detector data, we perform a statistical analysis of both the input energy flux from precipitating particles, and the observed occurrence of density irregularities in the northern hemisphere cusp. By examining trends in the two data sets relating to geomagnetic activity, we conclude that observations of irregularities in the cusp grows increasingly likely during storm‐time, whereas the precipitating particle energy flux does not. We thus find a weak or nonexistent statistical link between geomagnetic activity and precipitating particle energy flux in the cusp. This is a result of a previously documented tendency for the cusp energy flux to maximize during northward IMF, when density irregularities tend not to be widespread, as we demonstrate. At any rate, even though ionization and subsequent density gradients directly caused by soft electron precipitation in the cusp are not to be ignored for the trigger of irregularities, our results point to the need to scrutinize additional physical processes for the creation of irregularities causing scintillations in and around the cusp. While numerous phenomena known to cause density irregularities have been identified and described, there is a need for a systematic evaluation of the conditions under which the various destabilizing mechanisms become important and how they sculpt the observed ionospheric “irregularity landscape.” As such, we call for a quantitative assessment of the role of particle precipitation in the cusp, given that other factors contribute to the production of irregularities in a major way.

On the Impact of Geospace Weather on the Occurrence of M7.8/M7.5 Earthquakes on 6 February 2023 (Turkey), Possibly Associated with the Geomagnetic Storm of 7 November 2022

“…On Earth, there are two places where geomagnetic lines may constantly be filling with charged particles. These are the polar cusps where the solar wind plasma would directly access the atmosphere [9][10][11][12][13][14][15][16][17]. The magnetic local time determines the length of the polar cusps in longitude, and its largest extension is expected to be between 8 and 16 h MLT [17].…”

“…It has been well known for many decades that at the dayside of the high latitudes, there is a funnel-shaped area (polar cusp) where the solar wind plasma has direct access to the atmosphere. As summarized in [9], the polar cusp is a vital connection point for the solar wind-magnetosphere-ionosphere interaction, where the plasma density irregularities have a wide range of spatial scales. The reconnection of the solar wind magnetic field with the geomagnetic field at the dayside magnetopause impacts the polar cusp through flux transfer events that enhance ionospheric flow, input to the appearance of the field-aligned currents, and auroral particle precipitation.…”