Simultaneous Rocket and Scintillation Observations of Plasma Irregularities Associated With a Reversed Flow Event in the Cusp Ionosphere

Abstract

We present an overview of the ionospheric conditions during the launch of the Investigation of Cusp Irregularities 3 (ICI‐3) sounding rocket. ICI‐3 was launched from Ny‐Ålesund, Svalbard, at 7:21.31 UT on 3 December 2011. The objective of ICI‐3 was to intersect the reversed flow event (RFE), which is thought to be an important source for the rapid development of ionospheric irregularities in the cusp ionosphere. The interplanetary magnetic field was characterized by strongly negative Bz and weakly negative By. The EISCAT Svalbard radar (ESR) 32‐m beam was operating in a fast azimuth sweep mode between 180° (south) and 300° (northwest) at an elevation angle of 30°. The ESR observed a series of RFEs as westward flow channels that were opposed to the large‐scale eastward plasma flow in the prenoon sector. ICI‐3 intersected the first RFE in the ESR field of view and observed flow structures that were consistent with the ESR observations. Furthermore, ICI‐3 revealed finer‐scale flow structures inside the RFE. The high‐resolution electron density data show intense fluctuations at all scales throughout the RFE. The ionospheric pierce point of the GPS satellite PRN30, which was tracked at Hornsund, intersected the RFE at the same time. The GPS scintillation data show moderate phase scintillations and weak amplitude scintillations. A comparison of the power spectra reveals a good match between the ground‐based GPS carrier phase measurements and the spectral slope of the in situ electron density data in the lower frequency range. It demonstrates the possibility of modelling GPS scintillations from high‐resolution in situ electron density data.

Ionospheric Plasma Irregularities Based on In Situ Measurements From the Swarm Satellites

“…The climatology of ionospheric irregularities presented in this study also agrees with the loss of lock of GPS receiver onboard Swarm satellites (Buchert et al, 2015;Xiong et al, 2018). For a more direct comparison of in situ plasma density data with ground-based scintillations, we will need high-resolution plasma data (e.g., Jin, Moen, et al, 2019). One can also conduct a large statistical study of ground-based ionospheric scintillations to verify the agreement with the climatology of in situ measurements.…”

On the Production of Ionospheric Irregularities Via Kelvin‐Helmholtz Instability Associated with Cusp Flow Channels

“…Having preexisting high density such as the high‐latitude plasma reservoir in our case appears thus to be a crucial component for the onset of enhanced scintillation. One plausible explanation for the higher scintillation level we observe compared to one associated with the RFE in Jin et al () could indeed be related to the presence of the high‐density region in our case. The latter RFE was characterized by conditions (flow shears, temperatures, densities, and vTEC) fairly similar to the ones we measure in our trough.…”

Ionospheric Plasma IRregularities ‐ IPIR ‐ Data Product Based on Data From the Swarm Satellites

“…The IPIR dataset has already been used in addressing the structuring of plasma at high latitudes. The climatological study revealed interhemispheric asymmetry in plasma structuring, with more pronounced and widely distributed irregularities in the southern hemisphere, whereas in the northern hemisphere the plasma irregularities are commonly attributed to the cusp region and the nighttime auroral oval (Jin et al., 2019 ; Jin & Xiong, 2020 ). Several years of data revealed seasonal characteristics of the irregularities in the plasma density, where also clear dependence on the solar activity was demonstrated for the declining phase of the solar cycle.…”