HAZARDS AND RISK ASSESSMENT: Effects of a massive geomagnetic storm.
Rafael Fernando Daz Gaztelu 3777901 goxtad@gmail.com.
Abstract Geomagnetic storms are extraordinary variations of the Earths magnetic field at the surface. Potions of energy from solar wind are transferred to the magnetosphere, altering the orientation and intensity of the Earths magnetic field and energising the particles that make it up. This affects communications, navigation systems, satellites and even electric supplies. In a modern society like the one we live in, so dependent on electronics and internet. A massive Geomagnetic storm would collapse the worlds dynamic to a point that is almost unimaginable.
Introduction Life on Earth started about 3.5 billion years ago, and as far as we know it was only possible because of the Sun. Most astronomers consider that the Earth is located in what is called the Goldilocks Zone of the Solar System, which is the orbital area in which the temperature is ideal for water to be in a liquid state on a planet. Life is thought to have started in the bottom of the ocean, and there it thrived for millions of years until it went out of the water. This delay is associated to the Suns radiation. And it wasnt until the formation of the ozone layer in the upper atmosphere that vegetation and some aquatic animals dared to step out of the water and conquer land. This is just an example of how dangerous the Sun can be at some point. In this paper, the possibility of a severe solar event is studied.
The Sun The Sun is a G-type main sequence star at the center of our Solar System. Chemically, about of its mass is Hydrogen, the rest being mostly Helium. Its internal structure consist on the Core, with a density of 150 g/cc and a temperature close to 15.7 million K, is the region that produces an appreciable amount of thermal energy through fusion, the rest is heated by energy that is transferred outward from the core to the convective layers and then outside of the star. The thermal columns in the convection zone form an imprint on the surface of the Sun that is recognisable by us as the solar granulation. The turbulent convection of this outer part of the solar interior causes a small scale dynamo that produces magnetic north and south poles all over the surface of the Sun. One of the most important features in our star are Sunspots. These are relatively colder areas of the surface of the Sun (from 6000 K to approximately 4200 K), containing transitory magnetic fields. The number of Sunspots tends to vary periodically so that there exist what we call Solar Cycles, periods of maximal and minimal activity of the Sun. A Solar Cycle lasts 11 Earth years.
Figure 1. Graph depicting the correlation of several data, showing the existence of a recurrence pattern. The data considered are Irradiance (daily and annual ratios), Solar Flare Index, Sunspots observations and Radio Flux .
Along with these Sunspots there exists also what is known as Coronal Holes, which are areas in which plasma is less densely distributed and therefore less temperature is registered there and are also gateways to magnetic field lines. However, there are mainly two kinds of event that are almost unpredictable. These are the Solar Flares and the Coronal Mass Ejections.
Solar Flares Solar Flares are intense energy releases produced in the Solar Corona and they are thought to be produced by the reconnection of magnetic field lines. The amount of energy released in the biggest possible Solar Flare could be compared to 40 billion Hiroshima nuclear blasts and they radiate throughout the whole electromagnetic spectrum, from Gama Rays and X-rays including visible up to long wavelengths. Coronal Mass Ejection A Coronal Mass Ejection (CME) is a massive burst of solar wind and magnetic fields rising above the Solar Corona or being released into space. These phenomena are often associated with other forms of solar activity such as solar flares. Most ejections originate from active regions on the Suns surface, such as groupings of sunspots associated with frequent flares. Near solar maxima the sun produces about three CMEs every day, whereas near solar minima there is about one CME every five days. The ejected material is plasma consisting mainly of electrons and protons but may contain small quantities of heavier elements such as helium, oxygen and even iron. When the ejection is directed towards Earth and reaches it, the shock wave of the travelling mass of Solar Energetic Particles causes what we call a geomagnetic storm that may disrupt the Earths magnetosphere, compressing it on the day side and extending the night -side magnetic tail. When the magnetosphere reconnects on the night-side, it releases power on the order of terawatt scale, which is directed back toward the Earths upper atmosphere. These solar energetic particles can cause particularly strong aurorae in large regions around Earths magnetic poles, also known as Northern Lights or Southern Lights, depending on the pole. They can also disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages. Coronal Mass Ejections reach velocities between 200 km/s up to 3200 km/s (SOHO/LASCO 1996, 2003) and its frequency depends on the phase of the solar cycle. However, CMEs typically reach Earth one to five days after leaving the Sun. during their propagation, they interact with the solar wind and the interplanetary magnetic field, resulting in a deceleration or acceleration to finally pair with solar winds speed.
The Carrington Event and other important Geomagnetic Solar Storms. The solar storm of 1859, also known as the Carrington Event was a powerful geomagnetic solar storm during the 10th solar cycle. A solar flare and a CME produced a solar storm which hit the Earths magnetosphere and induced the largest known geomagnetic storm which was observed and recorder by Richard C. Carrington. From the 28th of August until the 2nd of September 1859, numerous sunspots and slar flares were observed on the Sun. On the 1 st of September, Richard Carrington observed the largest flare which caused a major CME to travel directly toward Earth, taking about 17 hours to reach it.
Fig XX: Sunspots sketched by Richard Carrington on September the 1st 1859. These are believed to be the origin of the Carrington event.
Aurorae were seen all around the world, even over the Caribbean; those over the Rocky Mountains were so bright that their glow awoke gold miners, who began preparing breakfast. They were so bright one could read a book with their light. Telegraph systems all over Europe and North America failed, in most cases shocking telegraph operators. Telegraph pylons threw sparks and telegraph paper spontaneously caught fire. Some telegraph systems continued to send and receive messages despite having been disconnected from their power supplies. Ice cores showed evidence that events of similar intensity recur at an average rate of approximately once per 500 years. Date August 28, 1859 Name Carrington Event Effects Telegraph disturbances. People in contact with apparatus shocked. Equipment on fire. Aurorae worldwide. Telegraph transmissions interrupted. People in contact with apparatus shocked. Switchboards on fire and sending keys melted. Sparks and electric balls hovering. Solar prominence seen with the naked eye through smoked glass. Power cuts in North America. Telegraph disruptions worldwide. HydroQuebecs power grid destroyed. Power cut that lasts 9 hours.
November 18, 1882
The transit of Venus Storm
May 13, 1921
The New York Railroad Storm
March 13, 1989
The Quebec Blackout Storm
Effects Intense solar flares release very high-energy particles that can cause radiation poisoning to humans and mammals in general in the same way as low-energy radiation from nuclear blasts. Earths atmosphere and magnetosphere allow adequate protection at groun d level, but astronauts in space are subject to potentially lethal doses of radiation. The penetration of high-energy particles into living cells can cause chromosome damage, cancer, and a host of other health problems. Large doses can be fatal immediately. Many communication systems use the ionosphere to reflect radio signals over long distances. Ionospheric storms can affect radio communication at all latitudes. Some radio frequencies are absorbed and others are reflected, leading to rapidly fluctuating signals and unexpected propagation paths. Damage t communication satellites can disrupt non-terrestrial telephone, television, radio and internet links. GPS would be adversely affected when solar activity disrupts their signal propagation. Power lines would also be affected terribly. The nearly direct currents induced in these lines from geomagnetic storms are harmful to electrical transmission equipment, especially generators and transformers, inducing core saturation, constraining their performance 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 throughout a system. According to a study by Metatech corporation, a storm with a strength comparative to that of 1921 would destroy more than 300 transformers and leave over 130 million people without power, with a cost totaling several trillion dollars. A massive solar flare could kill the electric supply for months.
Precautions By receiving geomagnetic storm alerts and warnings (e.g. by the Space Weather Prediction Center; via Space Weather satellites like SOHO or ACE) power companies can minimise damage to power transmission equipment by momentarily disconnecting transformers or by inducing temporary blackouts. References - Carrington, R. C. Description of a Singular Appearance seen in the Sun on September 1, 1859. Monthly Notices of the Royal Astronomical Society, Vol. 20, p.13-15. - Phillips A. Severe Space Weather. Social and economic impacts. 2009. NASA.
