Space weather challenges of the polar cap ionosphere

TL;DR

This study investigates space weather phenomena in the polar cap ionosphere, focusing on plasma instabilities and scintillations, using multi-instrument data to improve forecasting models for high-latitude scintillations.

Contribution

It combines multi-instrument observations to link plasma instabilities with scintillations and demonstrates the use of SuperDARN for tracking polar cap patches.

Findings

Scintillations are mainly caused by multi-scale structures from instability processes.

SuperDARN can effectively track polar cap patches and forecast their movement.

Cusp ionosphere shows high scintillation activity related to filamentary precipitation.

Abstract

This paper presents research on polar cap ionosphere space weather phenomena conducted during the European Cooperation in Science and Technology (COST) action ES0803 from 2008 to 2012. The main part of the work has been directed toward the study of plasma instabilities and scintillations in association with cusp flow channels and polar cap electron density structures/patches,which is considered as critical knowledge in order to develop forecast models for scintillations in the polar cap. We have approached this problem by multi-instrument techniques that comprise the EISCAT Svalbard Radar, SuperDARN radars, in-situ rocket, and GPS scintillation measurements. The Discussion section aims to unify the bits and pieces of highly specialized information from several papers into a generalized picture. The cusp ionosphere appears as a hot region in GPS scintillation climatology maps. Our results are consistent with the existing view that scintillations in the cusp and the polar cap ionosphere are mainly due to multi-scale structures generated by instability processes associated with the cross-polar transport of polar cap patches. We have demonstrated that the SuperDARN convection model can be used to track these patches backward and forward in time. Hence, once a patch has been detected in the cusp inflow region, SuperDARN can be used to forecast its destination in the future. However, the high-density gradient of polar cap patches is not the only prerequisite for high-latitude scintillations. Unprecedented high resolution rocket measurements reveal that the cusp ionosphere is associated with filamentary precipitation giving rise to kilometer scale gradients onto which the gradient drift instability can operate very efficiently... (continued)