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   https://www.jpl.nasa.gov/news/news.php?feature=6804   
      
   Solar Storms Can Drain Electrical Charge Above Earth   
   Jet Propulsion Laboratory   
   April 10, 2017   
      
   New research on solar storms finds that they not only can cause regions   
   of excessive electrical charge in the upper atmosphere above Earth's poles,   
   they also can do the exact opposite: cause regions that are nearly depleted   
   of electrically charged particles. The finding adds to our knowledge of   
   how solar storms affect Earth and could possibly lead to improved radio   
   communication and navigation systems for the Arctic.   
      
   A team of researchers from Denmark, the United States and Canada made   
   the discovery while studying a solar storm that reached Earth on Feb.   
   19, 2014. The storm was observed to affect the ionosphere in all of Earth's   
   northern latitudes. Its effects on Greenland were documented by a network   
   of global navigation satellite system, or GNSS, stations as well as   
   geomagnetic   
   observatories and other resources. Attila Komjathy of NASA's Jet Propulsion   
   Laboratory, Pasadena, California, developed software to process the GNSS   
   data and helped with the data processing. The results were published in   
   the journal Radio Science.   
      
   Solar storms often include an eruption on the sun called a coronal mass   
   ejection, or CME. This is a vast cloud of electrically charged particles   
   hurled into space that disturbs the interplanetary magnetic field in our   
   solar system. When these particles and the magnetic disturbances encounter   
   Earth's magnetic field, they interact in a series of complex physical   
   processes, and trigger perturbations in the Earth's magnetic field. Those   
   perturbations are called geomagnetic storms. The interactions may cause   
   unstable patches of excess electrons in the ionosphere, an atmospheric   
   region starting about 50 miles (80 kilometers) above Earth's surface that   
   already contains ions and electrons.   
      
   The 2014 geomagnetic storm was a result of two powerful Earth-directed   
   CMEs. The storm initially produced patches of extra electrons in the   
   ionosphere   
   over northern Greenland, as usual. But just south of these patches, the   
   scientists were surprised to find broad areas extending 300 to 600 miles   
   (500 to 1,000 kilometers) where the electrons were "almost vacuumed out,"   
   in the words of Per Hoeg of the National Space Research Institute at the   
   Technical University of Denmark, Lyngby. These areas remained depleted   
   of electrons for several days.   
      
   The electrons in the ionosphere normally reflect radio waves back to ground   
   level, enabling long-distance radio communications. Both electron depletion   
   and electron increases in this layer can possibly cause radio communications   
   to fail, reduce the accuracy of GPS systems, damage satellites and harm   
   electrical grids.   
      
   "We don't know exactly what causes the depletion," Komjathy said. "One   
   possible explanation is that electrons are recombining with positively   
   charged ions until there are no excess electrons. There could also be   
   redistribution -- electrons being displaced and pushed away from the region,   
   not only horizontally but vertically."   
      
   The paper is titled "Multiinstrument observations of a geomagnetic storm   
   and its effects on the Arctic ionosphere: A case study of the 19 February   
   2014 storm." Lead author Tibor Durgonics is a doctoral student at the   
   Technical University of Denmark. Richard Langley (University of New Brunswick,   
   Canada) provided data sets and interpretation.   
      
   JPL is a division of Caltech in Pasadena, California.   
      
   News Media Contact   
   Alan Buis   
   Jet Propulsion Laboratory, Pasadena, California   
   818-354-0474   
   Alan.Buis@jpl.nasa.gov   
      
   Written by Carol Rasmussen   
   NASA's Earth Science News Team   
      
   2017-103   
      
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