Editing Geomagnetic storm (section)

=== Infrastructure ===

It has been suggested that a geomagnetic storm on the scale of the [[solar storm of 1859]] today would cause billions or even trillions of dollars of damage to satellites, power grids and radio communications, and could cause electrical blackouts on a massive scale that might not be repaired for weeks, months, or even years.<ref name="nas2008"/> Such sudden electrical blackouts may threaten food production.<ref name="food">{{cite journal |last =Lassen | first = B |title=Is livestock production prepared for an electrically paralysed world? |journal=J Sci Food Agric |volume=93 |issue=1 |pages=2–4 | year=2013 | pmid=23111940 |doi=10.1002/jsfa.5939 | bibcode = 2013JSFA...93....2L |doi-access=free }}</ref>

==== Electrical grid ====

When [[magnetic field]]s move about in the vicinity of a conductor such as a wire, a [[geomagnetically induced current]] is produced in the conductor. This happens on a grand scale during geomagnetic storms (the same mechanism also influenced telephone and telegraph lines before fiber optics, see above) on all long transmission lines. Long transmission lines (many kilometers in length) are thus subject to damage by this effect. Notably, this chiefly includes operators in China, North America, and Australia, especially in modern high-voltage, low-resistance lines. The European grid consists mainly of shorter transmission circuits, which are less vulnerable to damage.<ref name="kappenman">{{cite news | url=https://spectrum.ieee.org/energy/the-smarter-grid/a-perfect-storm-of-planetary-proportions/0 | archive-url=https://web.archive.org/web/20120127072117/http://spectrum.ieee.org/energy/the-smarter-grid/a-perfect-storm-of-planetary-proportions/0 | url-status=dead | archive-date=27 January 2012 | title=A Perfect Storm of Planetary Proportions | work=[[IEEE Spectrum]] |date=February 2012 | access-date=2012-02-13 }}</ref><ref>Natuurwetenschap & Techniek Magazine, June 2009</ref>

The (nearly direct) currents induced in these lines from geomagnetic storms are harmful to electrical transmission equipment, especially [[transformer]]s—inducing core [[saturation (magnetic)|saturation]], constraining their performance (as well as tripping various safety devices), and causing coils and cores to heat up. In extreme cases, this heat can disable or destroy them, even inducing a chain reaction that can overload transformers.<ref>{{cite web |url=http://192.211.16.13/curricular/ENERGY/0708/articles/solar/SolarForecast07SkyTel.pdf|title=Solar Forecast: Storm AHEAD |archive-url=https://web.archive.org/web/20080911192808/http://192.211.16.13/curricular/ENERGY/0708/articles/solar/SolarForecast07SkyTel.pdf |archive-date=2008-09-11 |url-status=dead}}</ref><ref>{{Cite web|url=http://science.nasa.gov/headlines/y2009/21jan_severespaceweather.htm|title=NASA - Severe Space Weather--Social and Economic Impacts|date=24 January 2009|archive-url=https://web.archive.org/web/20090124153337/http://science.nasa.gov/headlines/y2009/21jan_severespaceweather.htm |accessdate=27 June 2023|archive-date=24 January 2009 |url-status=dead}}</ref> Most generators are connected to the grid via transformers, isolating them from the induced currents on the grid, making them much less susceptible to damage due to [[geomagnetically induced current]]. 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.<ref>{{cite book |title=Severe Space Weather Events: Understanding Societal and Economic Impacts : a Workshop Report |location=Washington, D.C. |publisher=National Academies, 2008 |url=http://www.nap.edu/openbook.php?record_id=12507&page=1 |date=15 November 2011 |pages=78,105,106|doi=10.17226/12507 |isbn=978-0-309-12769-1 }}</ref> The extent of the disruption is debated, with some congressional testimony indicating a potentially indefinite outage until transformers can be replaced or repaired.<ref>{{cite web |title=Testimony of the Foundation For Resilient Societies before the Federal Energy Regulatory Commission | url=https://www.resilientsocieties.org/uploads/5/4/0/0/54008795/resilient_societies_testimony_rm15-11-00_march_1_2016_tech_conference_final_feb_23_2016.pdf}}</ref> 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.<ref>{{cite web |url=https://www.frcc.com/Public%20Awareness/Lists/Announcements/Attachments/105/GMD%20Interim%20Report.pdf |title=2012 Special Reliability Assessment Interim Report: Effects of Geomagnetic Disturbances on the Bulk Power System |publisher=North American Electric Reliability Corporation |date=February 2012 |access-date=2013-01-19 |url-status=dead |archive-url=https://web.archive.org/web/20150908075507/https://www.frcc.com/Public%20Awareness/Lists/Announcements/Attachments/105/GMD%20Interim%20Report.pdf |archive-date=2015-09-08 }}</ref> 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.<ref>{{cite web |url=https://www.federalregister.gov/documents/2016/09/30/2016-23441/reliability-standard-for-transmission-system-planned-performance-for-geomagnetic-disturbance-events |title=Rule Reliability Standard for Transmission System Planned Performance for Geomagnetic Disturbance Events |date=September 30, 2016 |author=Federal Energy Regulatory Commission}}</ref>

Besides the transformers being vulnerable to the effects of a geomagnetic storm, electricity companies can also be affected indirectly by the geomagnetic storm. For instance, Internet service providers may go down during geomagnetic storms (and/or remain non-operational long after). Electricity companies may have equipment requiring a working Internet connection to function, so during the period the Internet service provider is down, the electricity too may not be distributed.<ref>Kijk magazine 6/2017, mentioned by Marcel Spit of Adviescentrum Bescherming Vitale Infrastructuur]</ref>

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. Preventive measures also exist, including preventing the inflow of GICs into the grid through the neutral-to-ground connection.<ref name="kappenman"/>

==== Communications ====

[[High frequency]] (3–30&nbsp;MHz) communication systems use the ionosphere to reflect radio signals over long distances. Ionospheric storms can affect radio communication at all latitudes. Some frequencies are absorbed and others are reflected, leading to rapidly fluctuating signals and unexpected [[radio propagation|propagation]] paths. TV and commercial radio stations are little affected by solar activity, but ground-to-air, ship-to-shore, [[shortwave]] [[Broadcasting|broadcast]] and [[amateur radio]] (mostly the bands below 30&nbsp;MHz) are frequently disrupted. Radio operators using HF bands rely upon solar and geomagnetic alerts to keep their communication circuits up and running.

Military detection or early warning systems operating in the high frequency range are also affected by solar activity. The ''[[over-the-horizon radar]]'' bounces signals off the ionosphere to monitor the launch of aircraft and missiles from long distances. During geomagnetic storms, this system can be severely hampered by radio clutter. Also some submarine detection systems use the magnetic signatures of submarines as one input to their locating schemes. Geomagnetic storms can mask and distort these signals.

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.{{citation needed|date=August 2016}} This can also happen on [[UHF]] and [[Super high frequency|SHF]] satellite communications, when an Earth station, a satellite and the Sun are in [[Sun outage|alignment]]. 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]].<ref>{{cite web |url=https://www.airsatone.com//gams |title=AirSatOne's Live Feed}}</ref> allows users to view observed and predicted space storms. Geophysical Alerts are important to flight crews and maintenance personnel to determine if any upcoming activity or history has or will have an effect on satellite communications, GPS navigation and HF Communications.

[[electrical telegraph|Telegraph]] lines in the past were affected by geomagnetic storms. Telegraphs used a single long wire for the data line, stretching for many miles, using the ground as the return wire and fed with [[Direct current|DC]] power from a battery; this made them (together with the power lines mentioned below) susceptible to being influenced by the fluctuations caused by the [[ring current]]. The voltage/current induced by the geomagnetic storm could have diminished the signal, when subtracted from the battery polarity, or to overly strong and spurious signals when added to it; some operators learned to disconnect the battery and rely on the induced current as their power source. In extreme cases the induced current was so high the coils at the receiving side burst in flames, or the operators received electric shocks. Geomagnetic storms affect also long-haul telephone lines, including undersea cables unless they are [[fiber optic]].<ref>{{Cite web|url=http://image.gsfc.nasa.gov/poetry/storm/storms.html|archive-url=https://web.archive.org/web/20050911073432/http://image.gsfc.nasa.gov/poetry/storm/storms.html|url-status=dead|title=image.gsfc.nasa.gov|archive-date=11 September 2005}}</ref>

Damage to communications satellites can disrupt non-terrestrial telephone, television, radio and Internet links.<ref>{{cite news|title=Solar Storms Could Be Earth's Next Katrina|newspaper = NPR.org|url=https://www.npr.org/templates/story/story.php?storyId=124125001|access-date=2010-03-04}}</ref> The [[United States National Academy of Sciences|National Academy of Sciences]] reported in 2008 on possible scenarios of widespread disruption in the 2012–2013 solar peak.<ref>{{cite book |title=Severe Space Weather Events—Understanding Societal and Economic Impacts: Workshop Report |publisher=National Academies Press |location=Washington, D.C. |date=2008 |doi=10.17226/12507 |isbn=978-0-309-12769-1 |url=http://www.nap.edu/catalog.php?record_id=12507#toc}}</ref> A solar superstorm could cause large-scale global months-long [[Internet outage]]s. A study describes potential mitigation measures and exceptions – such as user-powered [[Wireless mesh network|mesh networks]], related [[peer-to-peer]] applications and new protocols – and analyzes the robustness of the current [[Internet infrastructure]].<ref>{{cite news |title=Computer scientist warns global internet is not prepared for a large solar storm |url=https://techxplore.com/news/2021-08-scientist-global-internet-large-solar.html |access-date=22 September 2021 |work=techxplore.com |language=en}}</ref><ref>{{cite news |title=A Bad Solar Storm Could Cause an 'Internet Apocalypse' |url=https://www.wired.com/story/solar-storm-internet-apocalypse-undersea-cables/ |access-date=22 September 2021 |magazine=Wired}}</ref><ref>{{cite conference |last1=Jyothi |first1=Sangeetha Abdu |book-title=Proceedings of the 2021 ACM SIGCOMM 2021 Conference |title=Solar superstorms: Planning for an internet apocalypse |date=9 August 2021 |pages=692–704 |doi=10.1145/3452296.3472916 |publisher=Association for Computing Machinery|isbn=9781450383837 |doi-access=free }}</ref>

==== Navigation systems ====

[[Satellite navigation|Global navigation satellite systems (GNSS)]], and other navigation systems such as [[LORAN]] and the now-defunct [[Omega Navigation System|OMEGA]] are adversely affected when solar activity disrupts their signal propagation. The OMEGA system consisted of eight transmitters located throughout the world. Airplanes and ships used the very low frequency signals from these transmitters to determine their positions. During solar events and geomagnetic storms, the system gave navigators information that was inaccurate by as much as several miles. If navigators had been alerted that a proton event or geomagnetic storm was in progress, they could have switched to a backup system.

GNSS signals are affected when solar activity causes sudden variations in the density of the ionosphere, causing the satellite signals to [[Scintillation (astronomy)|scintillate]] (like a twinkling star). The scintillation of satellite signals during ionospheric disturbances is studied at [[High Frequency Active Auroral Research Program|HAARP]] during ionospheric modification experiments. It has also been studied at the [[Jicamarca Radio Observatory]].

One technology used to allow GNSS receivers to continue to operate in the presence of some confusing signals is [[Receiver Autonomous Integrity Monitoring]] (RAIM), used by GPS. However, RAIM is predicated on the assumption that a majority of the GPS constellation is operating properly, and so it is much less useful when the entire constellation is perturbed by global influences such as geomagnetic storms. Even if RAIM detects a loss of integrity in these cases, it may not be able to provide a useful, reliable signal.

==== Satellites ====

Geomagnetic storms and increased solar [[ultraviolet]] emission heat Earth's upper atmosphere, causing it to expand. The heated air rises, and the density at the orbit of [[satellite]]s up to about {{convert|1000|km|-2|abbr=on}} increases significantly. This results in increased [[Drag (physics)|drag]], causing satellites to slow and change [[orbit]] slightly. [[Low Earth orbit]] satellites that are not repeatedly boosted to higher orbits slowly fall and eventually burn up. [[Skylab]]'s 1979 destruction is an example of a spacecraft [[Atmospheric reentry|reentering]] Earth's atmosphere prematurely as a result of higher-than-expected solar activity.<ref>{{cite book|last1=Benson|first1=Charles Dunlap|first2=William David|last2=Compton|name-list-style=amp |year=1983 |url=https://history.nasa.gov/SP-4208/contents.htm|title=Living and Working in Space: A History of Skylab |publisher=NASA Scientific and Technical Information Office|id=SP-4208|oclc=8114293}}</ref> During the great geomagnetic storm of March 1989, four of the [[U.S. Navy]]'s navigational satellites had to be taken out of service for up to a week, the [[U.S. Air Force Space Command|U.S. Space Command]] had to post new [[orbital elements]] for over 1000 objects affected, and the [[Solar Maximum Mission]] satellite fell out of orbit in December the same year.<ref>{{cite journal |url=ftp://ftp.ngdc.noaa.gov/STP/SOLAR_DATA/Publications/March1989Events/EffectsoftheMarch1989SolarActivity-Allen%20et%20al%20-%201989.pdf |title=Effects of the March 1989 Solar Activity |author1=Joe Allen |author2=Lou Frank |author3=Herb Sauer |author4=Patricia Reiff |journal=Eos |date=November 14, 1989 |page=1488}}</ref>

The vulnerability of the satellites depends on their position as well. 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.<ref name=NYT>{{cite news |url=https://www.nytimes.com/1990/06/05/science/dip-on-earth-is-big-trouble-in-space.html |title='Dip' on Earth is Big Trouble in Space |work=[[The New York Times]] |last=Broad |first=William J. |date=5 June 1990 |access-date=31 December 2009}}</ref>

==== Pipelines ====

Rapidly fluctuating geomagnetic fields can produce [[geomagnetically induced current]]s in [[Pipeline transport|pipeline]]s. This can cause multiple problems for pipeline engineers. Pipeline flow meters can transmit erroneous flow information and the [[corrosion]] rate of the pipeline can be dramatically increased.<ref>{{Cite journal |last1 = Gummow |first1 = R |title = GIC effects on pipeline corrosion and corrosion control systems |journal = Journal of Atmospheric and Solar-Terrestrial Physics |volume = 64 |page = 1755 |date = 2002 |doi = 10.1016/S1364-6826(02)00125-6|bibcode = 2002JASTP..64.1755G |last2 = Eng |first2 = P |issue = 16 }}</ref><ref>{{Cite journal |last1 =Osella |first1 =A |last2 =Favetto |first2 =A |last3 =López |first3 =E |title =Currents induced by geomagnetic storms on buried pipelines as a cause of corrosion |journal =Journal of Applied Geophysics |volume =38 |page =219 |date =1998 |doi =10.1016/S0926-9851(97)00019-0|bibcode = 1998JAG....38..219O |issue =3 }}</ref>