Solar flares aren’t generally considered much of a threat since they occur infrequently, aren’t always directed towards the earth and can be small enough that they do not cause any damage. Regardless, the possibility remains that a solar flare could impact your organization.
In fact, solar activity has picked up in recent years; we are headed into what is known as the solar maximum of the solar cycle. The solar maximum is expected to occur in May 2013 and NASA has predicted this will be “the most intense solar maximum in fifty years.”
Before we get into the potential impacts we need to take a high-level look at what occurs when the Sun experiences a solar flare. It is important to note that while we have learned a great deal about our Sun in the last several decades and we have written records on the Sun’s cycles for the last 400 years there is still much we do not know.
First, Some Science
Increased sunspots are looked at as an indicator for increased solar flare activity. A solar flare is defined as a sudden, rapid and intense variation in brightness. They occur when the magnetic energy built up in the solar atmosphere of our Sun is suddenly released. The solar flare itself is a burst of radiation resulting from the release of the Sun’s magnetic energy. This radiation is released as electromagnetic waves that travel at or near the speed of light. Due to the speed at which these waves travel flares can impact the Earth with little warning.
Coronal mass ejections (CMEs) are often associated with solar flares. CMEs are huge clouds or “bubbles” of gas, plasma and magnetic fields that are ejected from the Sun over the course of several hours. CMEs can only impact the Earth when the eruption occurs in the direction of our planet or if the planet passes through a CME that just occurred. When a CME strikes the Earth and Earth’s magnetosphere it can cause massive disturbances and can do so with often catastrophic results.
Due to the nature of these disturbances they are often called geomagnetic storms. Geomagnetic storms can be caused by either a CME or high-speed stream of solar wind (scientifically called co-rotating interaction region or CIR).
All geomagnetic storms have the same effect of causing plasma to move through the magnetosphere. This movement of plasma causes an increase in electrical currents in the magnetosphere and the ionosphere. The increased electrical currents cause several additional space weather phenomena called solar energetic particle (SEP) events, geomagnetically induced currents (GIC), and ionospheric disturbances. Each of these phenomena has its own unique hazards.
GICs produce temporary disturbances to the Earth’s magnetosphere and can introduce damaging electric currents to power grids and pipelines, as well as to other long conductive systems. Ionospheric disturbances result in interference to radar, radio and navigational systems, while SEP events are most likely to cause increased radiation hazards to spacecraft, astronauts and, potentially, aircraft.
Of the three, the most serious threat is from GICs since they can cause serious long-term damage to the electric grid and telecommunications infrastructure, leading to a cascade of failures. Well get to those failures and the hazards they present in more detail later. For now, let’s look at how these threats are measured and classified.
Measuring Solar Activity
Solar flares are classified using an alphanumeric designator. On one end of the spectrum are A- and B-Class flares, which are small eruptions with little to no noticeable effects on the Earth. At the other end of the spectrum are X-class flares: gigantic events that are often associated with significant CMEs.
Table 1: Classification Of Solar Flares
A1 - A9
B1 - B9
C1 - C9
M1 - M9
X1 - X9+
The good news is that CMEs generally take 24 hours to four days to affect the Earth, so we should have some warning. The bad news is that most businesses rely heavily on modern technology in order to function and most businesses including our critical infrastructure are unprepared for massive geomagnetic storms.
Classification of geomagnetic storms is a bit different and several scales and indexes are used to measure geomagnetic storms. Even though different scales and indexes exist, their classifications range from quiet at one end of the spectrum to extreme on the opposite end. They are classified by their relative disturbance of the Earth’s magnetic field.
In Table 2 below we show an example of one of the most widely referenced methods of classification, the G-scale, from the National Oceanic and Atmospheric Administration (NOAA). The G-scale is based on the K-index, which is also included for your reference.
Table 2: Classification Of Geomagnetic Storms
NOAA also has scales for space weather associated with solar flares that can result in solar radiation storms and radio blackouts, but for purposes of this article -- and not getting too technical -- I’ll stick with just the effects of geomagnetic storms. Armed with this information you should be able to monitor the current space weather conditions through NOAA’s Space Weather Now site.
A Brief History Of Solar Storms
Several solar storms have caused both minor and major impacts to our infrastructure. Here are some of the notable geomagnetic storms:
October 19 through November 5, 2003 – Seventeen major flares erupted from the Sun, one of which was the largest ever. The x-rays from that flare were so intense they overloaded the GOES satellite sensors. It was eventually estimated to be an X45 event. Fortunately the accompanying particle and magnetic release was not directed at the Earth. If it was, damage to satellites and electrical networks could have been in the trillions of dollars.
March 9 through 13, 1989 – A CME resulted in a geomagnetic storm in the Canadian province of Quebec. It resulted in the collapse of the Hydro-Quebec power grid and a power outage for six million people lasting nine hours.
September 1, 1859 – A huge solar flare now known as the Carrington Event (after the famous astronomer that observed it) caused a CME. The CME reached Earth 18 hours later disrupting telegraph transmissions, burning up telegraph wires and reducing them to ash, shocking telegraph operators, and in some cases causing fires.
The hazards of a solar storm can include radiation poisoning to humans in space or high altitudes, the disruption of communications and navigation systems, dangerously high voltages on pipelines, and destructive currents to the power grids. NOAA has established a list of effects that can be expected, shown below in Table 3.
Table 3: Geomagnetic Storm Effects
Widespread voltage control problems and protective system problems can occur, some grid systems may experience complete collapse or blackouts. Transformers may experience damage.
May experience extensive surface charging, problems with orientation, uplink/downlink and tracking satellites.
Pipeline currents can reach hundreds of amps, HF (high frequency) radio propagation may be impossible in many areas for one to two days, satellite navigation may be degraded for days, low-frequency radio navigation can be out for hours, and aurora has been seen as low as Florida and southern Texas (typically 40° geomagnetic lat.).
Possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.
May experience surface charging and tracking problems, corrections may be needed for orientation problems.
induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45° geomagnetic lat.).
Voltage corrections may be required, false alarms triggered on some protection devices.
Surface charging may occur on satellite components, drag may increase on low-Earth-orbit satellites, and corrections may be needed for orientation problems.
intermittent satellite navigation and low-frequency radio navigation problems may occur, HF radio may be intermittent, and aurora has been seen as low as Illinois and Oregon (typically 50° geomagnetic lat.).
High-latitude power systems may experience voltage alarms, long-duration storms may cause transformer damage.
Corrective actions to orientation may be required by ground control; possible changes in drag affect orbit predictions.
HF radio propagation can fade at higher latitudes, and aurora has been seen as low as New York and Idaho (typically 55° geomagnetic lat.).
Weak power grid fluctuations can occur.
Minor impact on satellite operations possible.
Migratory animals are affected at this and higher levels; aurora is commonly visible at high latitudes (northern Michigan and Maine).
With an appreciation for the increased frequency of these storms and the damage they can cause, we should begin taking steps to protect vulnerable equipment.
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 National Weather Service. Space Weather Prediction Center. (May 8, 2009) Solar Cycle Progression. Retrieved September 25, 2012 from http://www.swpc.noaa.gov/SolarCycle/
 National Aeronautics and Space Administration, NASA. (March 10, 2006) Solar Storm Warning Retrieved September 25, 2012 from http://science.nasa.gov/science-news/science-at-nasa/2006/10mar_stormwarning/
 National Aeronautics and Space Administration, NASA. (n.d.) Retrieved September 25, 2012 from http://hesperia.gsfc.nasa.gov/sftheory/flare.htm
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 NOAA. NOAA Space Weather Scales. (n.d.) NOAA Space Weather Scales Retrieved September 26, 2012 from http://www.swpc.noaa.gov/NOAAscales/
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