Much like a temperamental teenager, the sun has been acting up of late. As it approaches the peak of the 11-year solar activity cycle, predicted to occur next May, it has been displaying an increasing number of angry outbursts. These solar storms are technically called solar flares and are giant eruptions of radiation from the sun's atmosphere that cause significant brightening of the area where they occur. Solar flares are sometimes followed by coronal mass ejections (CMEs), which spew charged and magnetized particles into space.  Depending on the direction of their release, these particles sometimes reach Earth where they occasionally damage satellites and disrupt terrestrial power grids. In 1989 a solar storm knocked out electricity across Quebec for nine hours. In 2003 a solar storm crippled South Africa's power supply by damaging 15 large transformers, according to John Kappenman, an expert on how solar storms affect power grids.

On July 12, as a huge CME headed toward Earth, forecasters warned of possible power outages, spurring flight controllers to reroute aircraft on polar routes to lower latitudes, away from the shower of energetic particles. That storm produced spectacular auroral displays but caused no outages. Other CMEs followed on July 19 and 23 but, again, neither caused power failures.

Why is it that some CMEs cause disruptions whereas others of a similar magnitude or even larger do not? Experts, aided by new models, point to a couple of factors.

"For the first time, space weather forecasters now have models and tools for predicting how a CME is released from the sun, accelerated out into the solar wind, and ultimately ends up colliding with Earth's magnetosphere creating the geomagnetic storms that impact so many technologies and systems," says Rodney Viereck of the National Oceanic and Atmospheric Administration's (NOAA) Space Environment Center. Viereck's team is responsible for forecasts of geomagnetic storms caused by solar outbursts.

The first factor that influences whether a CME will be disruptive is the direction in which the charged particles are emitted. "Solar storms propagate like a bullet," says Tamas Gombosi, director of the Center of Space Environment Modeling at the University of Michigan. "Sometimes the bullets miss the Earth. When they originate far from the [sun's] central meridian that is facing the Earth, they miss the Earth."

The other factor is the orientation of the magnetic field of the charged particles streaming toward Earth. How the magnetic field of the CME interacts with Earth's magnetosphere, the magnetic shell covering and protecting the planet, determines how severe any terrestrial effects will be, notes Gombosi, who has built models of the interaction.

In general, if the charged particles from a CME hit Earth's magnetosphere head on and the ejection has a strong magnetic field pointing south, then the disruptive effects are greater, Gombosi says.

According to him, some storms are most troublesome because of a process called magnetic reconnection, in which the magnetic field of the CME interacts directly with the Earth's magnetic field. During the interaction, the magnetic field lines that normally connect the planet's north and south poles may get reconfigured and essentially plug into the CME's field lines for a short time, then disconnect and regroup again into a north-south configuration.

"When the CME's magnetic field has a big southward component, there is a high probability of reconnection," Gombosi explains. "On the other hand, if there is a high northward component, there is a low probability of reconnection."

The way reconnection disturbs terrestrial power grids is complex but, in essence, the process mimics what happens in electric generators, where a fluctuating magnetic field (usually a moving magnet) produces a current in a coil of wire, says Adam Szabo, director of NASA's Heliophysics Laboratory. "Just as in regular electric generators, when moving magnetic fields cross long electrical conductors, electric currents will be generated. Power lines are such long conductors. The generated excess current can overload transformers and substations causing a domino effect of outages."

5 Comments

1. 1. Mark Goldes 05:19 PM 8/23/12

   This is very good news but we face a potential nuclear nightmare unless a massive program takes wise steps to prevent it.
   
   See the second of Three Ticking Time Bombs on the Aesop Institute website.
   
   New technology can prevent grid collapse in a strong solar storm, but will not be in production until early next year.
   
   Decentralizing energy would be extremely wise. 50 million more solar roofs are a good place to begin.

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2. 2. Asteroid Miner 12:44 AM 8/25/12

   1. The Aesop Institute is full of nonsense.
   Notice that we are still alive after all 800 bombs were exploded in the atmosphere. In fact, those 800 bombs had an effect of less than a 1% of the NATURAL BACKGROUND RADIATION.
   
   You should consider that the Aesop Institute may be a creation of some industry.
   
   2. There is no mortal threat from a solar storm.
   
   3. Global Warming really is an existential threat. The cure is nuclear power to replace coal. Coal is the source of 40% of the CO2 we generate.
   
   573 certified deaths were due to evacuation-related stress at Fukushima. Zero due to radiation. February 4, 2012
http://www.beyondnuclear.org/home/2012/2/4/japanese-authorities-recognize-573-deaths-related-to-fukushi.html
   ZERO deaths were caused by radiation. 573 deaths were caused by the evacuation that was forced by officials. Fukushima's natural background radiation is still higher than the radiation from the reactor leak. Fukushima's natural background radiation plus the radiation from the reactor leak is still less than the natural background radiation here. Natural background radiation varies greatly from place to place. Our background radiation is above 350 milli rem/year.
   "milli" means ".001"
   350 milli rem/year means 0.350 rem/year
   People living in the city of Ramsar, Iran have a background radiation of 10 rems/year
   
   Please read this book: "Radiation and Reason, The impact of Science on a culture of fear" by Wade Allison.
   http://www.radiationandreason.com/
   Professor Allison says we can take up to 10 rems per month, a little more than 1000 times the present "legal" limit. The old limit was 5 rems/lifetime. A single dose of 800 rems could kill you, but if you have time to recover between doses of 10 rems, no problem. It is like donating blood: You see "4 gallon donor" stickers on cars. You know they didn't give 4 gallons all at once. There is a threshold just over 10 rems. You are getting .35 rems/year NATURAL background radiation right where you are right now.
   
   Natural Background Radiation is radiation that was always there, 1000 years ago, a million years ago, etc. Natural Background Radiation comes from the rocks in the ground and from exploding stars thousands of light years away. All rocks contain uranium. Radon gas is a decay product of uranium.
   
   Reference book: "The Rise of Nuclear Fear" by Spencer Weart.

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3. 3. hippocraticus 06:55 AM 9/3/12

   Might not solar flares damage solar panels?

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4. 4. Asteroid Miner in reply to hippocraticus 07:54 AM 9/3/12

   No. Solar flares can't damage solar panels. But you could get a sunburn. The solar output of UV C varies over a range of 100,000.
   
   You can keep track of solar storms at http://spaceweather.com
   Solar flares are common events. They happen all the time.
   
   
   Might I ask you to go to college and get a degree in physics?
   

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5. 5. Eric55 10:43 AM 4/10/13

   Question:
   Can solar storms damage solar panels?

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