Geomagnetic storm
[2] In 1989, a geomagnetic storm energized ground induced currents that disrupted electric power distribution throughout most of Quebec[3] and caused aurorae as far south as Texas.
[11] Chapman and Ferraro's work drew on that of, among others, Kristian Birkeland, who had used recently-discovered cathode-ray tubes to show that the rays were deflected towards the poles of a magnetic sphere.
The first scientific observation of the effects of a geomagnetic storm occurred early in the 19th century: from May 1806 until June 1807, Alexander von Humboldt recorded the bearing of a magnetic compass in Berlin.
It can be assumed that a massive coronal mass ejection was launched from the Sun and reached the Earth within eighteen hours—a trip that normally takes three to four days.
Ice cores show evidence that events of similar intensity recur at an average rate of approximately once per 500 years.
[14] In early August 1972, a series of flares and solar storms peaks with a flare estimated around X20 producing the fastest CME transit ever recorded and a severe geomagnetic and proton storm that disrupted terrestrial electrical and communications networks, as well as satellites (at least one made permanently inoperative), and spontaneously detonated numerous U.S. Navy magnetic-influence sea mines in North Vietnam.
[16] The March 1989 geomagnetic storm caused the collapse of the Hydro-Québec power grid in seconds as equipment protection relays tripped in a cascading sequence.
On July 14, 2000, an X5 class flare erupted (known as the Bastille Day event) and a coronal mass was launched directly at the Earth.
[22] The Wide Area Augmentation System (WAAS) operated by the Federal Aviation Administration (FAA) was offline for approximately 30 hours due to the storm.
By bouncing signals off ionospheric irregularities, which move with the field lines, one can trace their motion and infer magnetospheric convection.
At polar regions, directly linked to the solar wind, large-scale ionospheric anomalies can be successfully modeled, even during geomagnetic super-storms.
[26] At smaller scales (comparable to a degree of latitude/longitude) the results are difficult to interpret, and certain assumptions about the high-latitude forcing uncertainty are needed.
Notably, this chiefly includes operators in China, North America, and Australia, especially in modern high-voltage, low-resistance lines.
However, a transformer that is subjected to this will act as an unbalanced load to the generator, causing negative sequence current in the stator and consequently rotor heating.
A 2008 study by Metatech corporation concluded that a storm with a strength comparable to that of 1921 would destroy more than 300 transformers and leave over 130 million people without power in the United States, costing several trillion dollars.
[33] The extent of the disruption is debated, with some congressional testimony indicating a potentially indefinite outage until transformers can be replaced or repaired.
[34] These predictions are contradicted by a North American Electric Reliability Corporation report that concludes that a geomagnetic storm would cause temporary grid instability but no widespread destruction of high-voltage transformers.
The report points out that the widely quoted Quebec grid collapse was not caused by overheating transformers but by the near-simultaneous tripping of seven relays.
[35] In 2016, the United States Federal Energy Regulatory Commission adopted NEARC rules for equipment testing for electric utilities.
Implementation of any upgrades needed to protect against the effects of geomagnetic storms was required within four years, and the regulations also directed further research.
[37] By receiving geomagnetic storm alerts and warnings (e.g. by the Space Weather Prediction Center; via Space Weather satellites as SOHO or ACE), power companies can minimize damage to power transmission equipment, by momentarily disconnecting transformers or by inducing temporary blackouts.
[29] High frequency (3–30 MHz) communication systems use the ionosphere to reflect radio signals over long distances.
Military detection or early warning systems operating in the high frequency range are also affected by solar activity.
The Federal Aviation Administration routinely receives alerts of solar radio bursts so that they can recognize communication problems and avoid unnecessary maintenance.
When an aircraft and a ground station are aligned with the Sun, high levels of noise can occur on air-control radio frequencies.
In order to prevent unnecessary maintenance on satellite communications systems aboard aircraft AirSatOne provides a live feed for geophysical events from NOAA's Space Weather Prediction Center.
A study describes potential mitigation measures and exceptions – such as user-powered mesh networks, related peer-to-peer applications and new protocols – and analyzes the robustness of the current Internet infrastructure.
Geomagnetic storms and increased solar ultraviolet emission heat Earth's upper atmosphere, causing it to expand.
The South Atlantic Anomaly is a perilous place for a satellite to pass through, due to the unusually weak geomagnetic field at low Earth orbit.
[48][49] Earth's atmosphere and magnetosphere allow adequate protection at ground level, but astronauts are subject to potentially lethal radiation poisoning.
