solar storms

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HAZARDS AND RISK ASSESSMENT:

Effects of a massive geomagnetic storm.

Rafael Fernando Daz Gaztelu [email protected].

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.


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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 istransferred 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.


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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 includingvisible 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 thepole. 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.


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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

stof 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 Name Effects

August 28, 1859 Carrington Event Telegraph disturbances.

People in contact with apparatus shocked.Equipment on fire.Aurorae worldwide.

November 18, 1882 The transit ofVenus Storm

Telegraph transmissions interrupted.People in contact with apparatus shocked.Switchboards on fire and sending keys melted.Sparks and electric balls hovering.

May 13, 1921 The New YorkRailroad Storm

Solar prominence seen with the naked eyethrough smoked glass.Power cuts in North America.

Telegraph disruptions worldwide.

March 13, 1989 The Quebec

Blackout Storm

HydroQuebecs power grid destroyed.

Power cut that lasts 9 hours.


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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 ground 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.

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