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Risks posed by Geomagnetic Storms

Image taken from karthaus.eu

By Umay Salma

The sun is not as quiet as it seems from the earth. At the surface of the sun, there are constant explosions which are bombarding out electrons, protons, and radio through X-rays. These particles are emitted through the sun and travel through the space at 300 to 400 kilometers per second to hit the outer atmosphere of earth after four days. This is a normal case scenario and it doesn’t produce any significant effect on Earth’s surface.

However, occasionally, the eruption is violent and instead of some charged particles, the sun throws out billions of tons of charged particles. The solar wind at these times is really hard with speed reaching over 2000 km/sec. The particle densities and temperature are very high under these circumstances. Also, the solar winds are now organized into strong magnetic fields. When it hits the Earth’s upper atmosphere, the solar wind gets connected with the Earth’s magnetosphere. Both the fields interact and earth’s magnetosphere is expanded. The long tail-like portion that streams out from the nighttime side of the planet is also stretched. This magnetotail is extended until it becomes unstable and breaks into two.

One portion gets separated from the Earth and flies away into the space. The rest of it comes back to the earth like a broken rubber band. During this process, plasma is forced back into Earth’s upper atmosphere, a large current of more than a million amperes is built up at an altitude of 100km. This current is called electrojet and it produces brilliant colored auroras. Auroras are normal to be seen and under those normal circumstances these extend over globe’s higher latitudes, but in case of a very large storm these can reach down to the lower latitudes too.
The Earth’s geomagnetic balance can also be disturbed by coronal mass ejections. The solar wind can strike the magnetosphere and create giant electromagnetic waves. Also, sometimes, the space weather at lower latitude can set off geomagnetic activity. This is lesser in intensity but longer in duration. This is equally damaging as the storms at higher latitudes.

All of this activity damages the life on ground in multiple stages. A geomagnetic storm on a very large scale would cause billions 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.[i] When the Earth’s magnetosphere is hit by the solar winds, it causes variations in it. This varying magnetic field of Earth induces electric fields and currents at the Earth’s surface in accordance with the Faraday’s Law of Electromagnetic Induction and Lenz’s Law. These geo-magnetically induced currents can flow in any available conductor. This includes high-voltage transmission lines, under-sea communication cables, oil and gas pipelines and railways. These networks now act as antennas channeling induced currents from the ground. A 300 A of GIC can burn a high-voltage transformer’s paper tape insulation and melt its copper winding.

Similarly, Systems such as GPS, LORAN, and the now-defunct OMEGA are adversely affected when solar activity disrupts their signal propagation. Also 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 satellites up to about 1,000 km (621 mi) increases significantly. This results in increased drag on satellites in space, causing them to slow and change orbit slightly.[ii]

Geomagnetic Storms

Image taken from earthchangesaffirmations.com

A geomagnetic storm today would be far more dangerous than it was some centuries ago because in those days the only electro-technology was telegraph but today almost everything runs on electric signals. High-voltage transformers are the most vulnerable to break in such a storm. The best known case of this occurred in 1989 in Quebec. High currents in the magnetosphere induce high currents in power lines, blowing out electric transformers and power stations. This is most likely to happen at high latitudes, where the induced currents are greatest, and in regions having long power lines and where the ground is poorly conducting. EHV transformers, which can handle voltages of 345 kV or higher, weigh about 200 tons and cost about $10 million each.[iii] If a storm knocks out many of the transformers today, the manufacturers will be unable to provide the replacement as neither there is a global stock for such transformers, nor is the designing and testing of one transformer an easy task. This situation might lead to a black-out for many days.

Charles Perrow, however thinks that we’re spending way extra resources on protecting ourselves against ‘imagined’ terrorists. On the contrary our focus should be on finding ways to decrease the catastrophe caused by floods, hurricanes and solar storms. In our complex interactive systems today hundreds of steps should go right to avoid disaster on a large scale. From the past observations of trends of attacks from Al-Qaeda, Perrow believes that most of the attacks are meant more to make a statement than to kill people. He also thinks that ‘the chances are extremely low that Middle Eastern terrorists will stage an attack on U.S. soil that kills at least 1000 people or harms the economy as much as the 2003 blackout did.’[iv] Officials of the Department of Homeland Security claim that they’re using techniques which will be productive against both natural disasters and human terrorists. These include ‘hiring, training, and equipping of ambulance drivers, paramedics, firefighters, and rescue workers.’ Perrow argues that we can’t fully protect the targets but we can reduce their sizes. For example, the policy should be to discourage people to live near volcanic sights such as Bay area or New Orleans however what we see is otherwise. He also gives examples of other concentrated targets such as tankers of milk, which can be contaminated with noxious gas, and chemical storage depots. I agree with his point that we should employ more techniques which counter the natural disasters and also to break the bigger targets into smaller ones because probably we can withstand more of smaller attacks than one big disaster. However, we can’t completely neglect the terrorist activities and hence, there should be an optimum division of resources to secure both ends.

References:

[i] Odenwald, Sten and Green, James. “Bracing the Satellite Infrastructure for a Solar Superstorm” scientificamerican.com August 2008.  [back to text]

[ii] Holman, Gordon. “Space Weather: What impact do solar flares have on human activities?”  [back to text]

[iii] Kappenman, John. “A perfect storm of planetary proportions.” IEEE Spectrum 49.2 (February 2012): 26-31.  [back to text]

[iv] Radasky, William. “Fear of frying.” IEEE Spectrum 51.9 (September 2014): 46-51.  [back to text]

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