From: baalke@zagami.jpl.nasa.gov   
      
   Nancy Neal/Don Savage   
   Headquarters, Washington                 December 8, 2003   
   (Phone: 202/358-1547)   
      
   Lindsay Renick Mayer/Bill Steigerwald   
   Goddard Space Flight Center, Greenbelt, Md.   
   (Phone: 301/286-8955)   
      
   RELEASE: 03-398   
      
   SUN'S POWER & VIOLENCE REVEALED AT AGU   
      
        New discoveries about the elusive rules governing the   
   sun's most violent phenomena will be presented at 6 p.m. EST   
   today at a press conference during the annual American   
   Geophysical Union Fall Meeting in San Francisco.   
      
   A team of solar scientists led by Dr. James Chen of the Naval   
   Research Library has confirmed the basic anatomy of massive   
   solar eruptions called Coronal Mass Ejections (CMEs) is a   
   twisted magnetic structure called a "magnetic flux rope," as   
   first hypothesized over 10 years ago.   
      
   A team, led by Dr. Jiong Qiu of the Center for Solar Research   
   at the New Jersey Institute of Technology, found a close   
   relationship between the rate of the release of magnetic   
   energy, called "magnetic reconnection," during solar flares   
   and the acceleration of CMEs.   
      
   CMEs are billion-ton eruptions of electrically charged-gas   
   (plasma) in the sun's atmosphere (corona). The fastest CMEs   
   are blasted into space at a speed of up to five million miles   
   per hour (eight million km/hr). Solar flares are giant   
   explosions that spew radiation and result in the heating of   
   solar gas and the acceleration of particles to nearly the   
   speed of light.   
      
   Magnetic reconnection is the twisting and snapping of   
   invisible magnetic field lines on the sun. When these fields   
   snap from buildup of magnetic energy, plasma is heated and   
   particles are accelerated, resulting in an eruption.   
   According to Dr. Qui's research, the eruptions speed up and   
   slow down in correlation with the reconnection rate. The   
   magnetic reconnection may then create and help maintain a   
   "magnetic flux rope" which, according to Dr. Chen, is present   
   at the earliest stages of the CME process.   
      
   Flux ropes are twisted or curved magnetic currents that run   
   through the sun's ionized gas, similar to electricity running   
   through the copper wires of a house. Much like pushing the   
   center of a slinky away from you while holding one end in   
   each hand, if the current is large enough, the flux rope will   
   expand outward and become more curved. If the center erupts   
   and expands away from the sun, it may encounter the Earth's   
   magnetic field (magnetosphere), transferring magnetic energy   
   and resulting in large electric currents. These currents can   
   shut down electrical systems on Earth and disrupt signals   
   from satellites and aircraft.   
      
   "The most basic unanswered question regarding flux rope   
   models is how and when the magnetic field passing through the   
   area becomes highly-energetic," said Dr. Gareth Lawrence, a   
   solar scientist at NASA's Goddard Space Flight Center,   
   Greenbelt, Md. who will help present this research at the AGU   
   Fall Meeting. "If we can answer that, maybe we can figure out   
   how to predict when and where a flux rope will strike the   
   magnetosphere. Better space weather prediction means more   
   reliable communications, power transmissions, and other   
   large-scale electromagnetic technologies. These are all in   
   the public interest," she added.   
      
   Numerous space-based and ground-based observatories   
   contributed to the research Lawrence will present. The space-   
   based observatories include NASA's Reuven Ramaty High Energy   
   Solar Spectroscopic Imager (RHESSI); NASA's Transition Region   
   and Coronal Explorer (TRACE); and ESA's Solar Heliospheric   
   Observatory (SOHO). Ground-based observatories include the   
   Big Bear Solar Observatory and the Owens Valley Solar Array.   
      
   For information about NASA on the Internet, visit:   
      
   http://www.nasa.gov   
      
      
   -end-   
      
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