Ionospheric Scintillation and Geomagnetic Disturbance Caused by Space Hurricanes

Abstract

A space hurricane is a large-scale, cyclone-shaped aurora characterized by a rotating magnetic structure and shears in plasma convection, driven by high-latitude magnetic reconnection. It typically forms near the magnetic poles in summertime, providing an efficient energy transport channel from the solar wind to the Earth's magnetosphere under northward interplanetary magnetic field conditions. Here, we present a detailed case study of a typical space hurricane that occurred on 20 August 2014 and its impact on the polar ionosphere in the Northern Hemisphere. Multi-instrument observations from the Eureka GNSS receiver, SWARM and Defense Meteorological Satellite Program (DMSP) satellites indicate that GPS signals experienced enhanced phase scintillation near a space hurricane, coinciding with regions of large plasma density gradients and flow shears. Based on these in situ measurements, we estimated growth timescales of ∼94 s for gradient-drift instability and ∼352 s for KHI, supporting the plausibility of both instabilities. These plasma instabilities likely generated small-scale irregularities responsible for the observed scintillation effects on satellite signals. Geomagnetic data from the Greenland ground stations revealed intense local geomagnetic disturbances, likely associated with enhanced Hall currents driven by the upward field-aligned currents linked to the space hurricane. In situ plasma observations from the DMSP and SWARM satellites revealed pronounced electron density enhancements and steep gradients on the morning side of the space hurricane, likely driven by ionospheric convection and soft particle precipitation. This study provides the first comprehensive insight into the space weather effects of space hurricanes.