New critical information regarding THEMIS was reported by Andreas Keiling, a space physicist at the University of California, Berkeley’s Space Sciences Laboratory, on Friday, April 24, on the last day of the General Assembly 2009 meeting of the European Geophysical Union (EGU) in Vienna, Austria. NASA’s suite of spacecraft called THEMIS (Time History of Events and Macroscale Interactions during Substorms) help shed light on cosmic storms’ inner workings.
The aurora borealis, also known as the northern lights, five miles outside Kearney, Neb., on the evening of May 14, 2005. Photo by Mark Urwiller
Further information about these storms could also help scientists learn about storms forecasting the possible damage to manmade devices such as power grids. A report by the National Academy of Sciences concluded that a major storm during the next peak could cripple power grids and other communications systems, with adverse effects leading to a potential loss of governmental control of the situation.
The THEMIS team further investigated space tornadoes that are funnels of hot charged particles around the Earth, and can reach speeds of over 1.6 million kilometers per hour (1 million miles per hour). As the ions circle they create what is known as auroras. Because of this great speed, the space tornadoes can produce electrical currents greater than 100,000 amperes (a 60-watt light bulb draws about half an ampere). The tornadoes then channel this current of flowing electric charge along twisted magnetic field lines into Earth’s ionosphere to ignite the auroras.
The five space probes that make up THEMIS lifted off in February 2007 on a mission to study the origin of magnetic storms that power the aurora (also known as the Northern and Southern Lights). In order for THEMIS to study the tornadoes they travel through them at approximately 40,000 miles above Earth, as simultaneously ground telescopes watch to confirm the observations.
What they learned was that the magnetic holes are produced in the magnetotail, which is the region of the magnetosphere on the side of the Earth that faces away from the Sun. As these holes are produced the magnetotail is stretched past its capacity releasing a gigantic burst of energy that produces two spiraling vortices that turn opposite of each other becoming plasma tornadoes or spiraling vortices.
The EGU General Assembly 2009 was again determined to be a great success convening with 9,088 scientists from all over the world assembling at one meeting that addressed all disciplines of the Earth, Planetary and Space Sciences. Twenty-six percent of the participants were students, and the program included 12,977 oral and poster presentations during the week, and was completed by an interesting exhibition from industry and publishing as well as a high number of side meetings.
The Rocket
THEMIS was thundered into orbit aboard a Delta II rocket. The Delta II is designed to boost medium-sized satellites and robotic explorers into space. NASA selected a model 7925-10 for this mission, which is a three-stage rocket equipped with nine strap-on motors and a protective 10-foot payload fairing.
Image to right: A Delta II launches the THEMIS spacecraft. Image credit: NASA/KSC
Joachim Raeder (University of New Hampshire), who also has published journal articles with respect to THEMIS and solar storms, states. “If the solar field has been aligned with the Earth’s for a while, we now know Earth’s field is heavily loaded with solar particles and primed for a strong storm. This discovery gives us a basic predictive capability for the severity of solar storms, similar to a hurricane forecaster’s realization that warmer oceans set the stage for more intense hurricanes. In fact, we expect stronger storms in the upcoming solar cycle. The sun’s magnetic field changes direction every cycle, and due to its new orientation in the upcoming cycle, we expect the clouds of particles ejected from the sun will have a field which is at first aligned with Earth, then becomes opposite as the cloud passes by.” [NASA]
