Space Weather: Space Hurricanes

What is a space hurricane?

A space hurricane is a massive, spiral-shaped geomagnetic storm that appears above the polar Ionosphere of Earth under exceptionally calm conditions. These hurricanes are connected to the aurora borealis phenomenon, as the funnel's electron precipitation produces huge, cyclone-shaped auroras. Scientists believe that such hurricanes occur in the polar regions of planets with magnetic fields.

In contrast, hurricanes (tropical cyclones) on Earth form within the atmosphere through thunderstorms and angular momentum from the Earth's rotation. They draw energy up from the ocean surface, while space hurricanes are formed by plasma interacting with magnetic fields and extract energy from the flow of the solar wind.

Characteristics of space hurricanes

Space hurricanes consist of plasmas, which are extremely hot ionized gases rotating at exceptionally high speeds, reaching up to 7,560 kilometres per hour (4,700 mph). In 2020, scientists identified a vast space hurricane that occurred over the Arctic, spanning a diameter of 1,000 kilometres (620 miles) in the Ionosphere, an ionized upper atmosphere at an altitude of 110–860 kilometres (68–534 miles), and roughly centred over the North Magnetic Pole, using observations made on 20 August 2014. The storm featured a cyclone-like auroral spot with multiple spiral arms, circular plasma vorticity with zero horizontal flow at its centre, a negative-to-positive bipolar magnetic structure, and a large and rapid deposition of energy and flux into the polar ionosphere.

Furthermore, the space hurricane rotated counter-clockwise and had multiple spiral arms similar to conventional hurricanes. The storm produced a massive cyclone-shaped aurora due to the precipitation of electrons, which rained down instead of water. In the central region surrounded by the rotating plasma, there was a persistent auroral spot linked to a strong, upward, field-aligned current caused by precipitating electrons.

Unlike conventional space weather disturbances, the space hurricane appeared during very calm geomagnetic conditions, with slow solar wind flow and a northward-pointing interplanetary magnetic field. A strongly southward orientation is necessary to drive conventional geomagnetic storms. This similarity to lower atmospheric hurricanes was noted by an Accuweather meteorologist, who mentioned that hurricanes required light winds aloft to form.



The effects of space hurricanes

According to researchers, the electron precipitation linked with the space hurricane could interfere with GPS satellites, radio systems, and radar, and also elevate drag on any satellites close by. Furthermore, it could alter the orbits of space debris of all sizes at low altitudes, which pose a growing threat to spacecraft in low Earth orbit. However, aside from these potential space weather impacts, the storm is predicted to have minimal effects on the planet.

The discovery of space hurricanes

The discovery of the space hurricane was made by a team of researchers from Shandong University in China who had observed the storm over the Arctic region on August 20, 2014, but only identified its nature in 2021. The research team included scientists from the United States, the United Kingdom, and Norway. During their observation, which lasted for 8 hours, the team noticed that the storm gradually dissipated. This event occurred during a period of low solar and geomagnetic activity, and it was the first time that such a hurricane-like storm had been observed in the upper atmosphere, leading to previous uncertainty about their existence. Researchers speculate that similar space storms may be relatively common in the Solar System and beyond, on planets with magnetic fields, because the storm observed in 2014 occurred during a period of low geomagnetic activity.