Hello All!   
      
   Hidden Portals in Earth's Magnetic Field    
      
   June 29, 2012: A favorite theme of science fiction is "the portal"--an   
   extraordinary opening in space or time that connects travelers to distant   
   realms.  A good portal is a shortcut, a guide, a door into the unknown. If   
   only they actually existed....   
      
   It turns out that they do, sort of, and a NASA-funded researcher at the   
   University of Iowa has figured out how to find them.   
      
   "We call them X-points or electron diffusion regions," explains plasma   
   physicist Jack Scudder of the University of Iowa.  "They're places where the   
   magnetic field of Earth connects to the magnetic field of the Sun, creating an   
   uninterrupted path leading from our own planet to the sun's atmosphere 93   
   million miles away."    
      
   http://www.youtube.com/watch?v=y3_vW5yrNek   
      
   A new ScienceCast video explains how hidden portals form--and how we can find   
   them. Play it   
      
   Observations by NASA's THEMIS spacecraft and Europe's Cluster probes suggest   
   that these magnetic portals open and close dozens of times each day.  They're   
   typically located a few tens of thousands of kilometers from Earth where the   
   geomagnetic field meets the onrushing solar wind.  Most portals are small and   
   short-lived; others are yawning, vast, and sustained.  Tons of energetic   
   particles can flow through the openings, heating Earth's upper atmosphere,   
   sparking geomagnetic storms, and igniting bright polar auroras.   
      
   NASA is planning a mission called "MMS," short for Magnetospheric Multiscale   
   Mission, due to launch in 2014, to study the phenomenon. Bristling with   
   energetic particle detectors and magnetic sensors, the four spacecraft of MMS   
   will spread out in Earth's magnetosphere and surround the portals to observe   
   how they work.   
      
   Just one problem:  Finding them.  Magnetic portals are invisible, unstable,   
   and elusive.  They open and close without warning "and there are no signposts   
   to guide us in," notes Scudder.    
      
   Data from NASA's Polar spacecraft, circa 1998, provided crucial clues to   
   finding magnetic X-points. Actually, there are signposts, and Scudder has   
   found them.   
      
   Portals form via the process of magnetic reconnection.  Mingling lines of   
   magnetic force from the sun and Earth criss-cross and join to create the   
   openings. "X-points" are where the criss-cross takes place.  The sudden   
   joining of magnetic fields can propel jets of charged particles from the   
   X-point, creating an "electron diffusion region."    
      
   To learn how to pinpoint these events, Scudder looked at data from a space   
   probe that orbited Earth more than 10 years ago.   
      
   "In the late 1990s, NASA's Polar spacecraft spent years in Earth's   
   magnetosphere," explains Scudder, "and it encountered many X-points during its   
   mission."   
      
   Because Polar carried sensors similar to those of MMS, Scudder decided to see   
   how an X-point looked to Polar. "Using Polar data, we have found five simple   
   combinations of magnetic field and energetic particle measurements that tell   
   us when we've come across an X-point or an electron diffusion region. A single   
   spacecraft, properly instrumented, can make these measurements."   
      
   This means that single member of the MMS constellation using the diagnostics   
   can find a portal and alert other members of the constellation. Mission   
   planners long thought that MMS might have to spend a year or so learning to   
   find portals before it could study them.  Scudder's work short cuts the   
   process, allowing MMS to get to work without delay.   
      
   It's a shortcut worthy of the best portals of fiction, only this time the   
   portals are real. And with the new "signposts" we know how to find them.    
      
   The work of Scudder and colleagues is described in complete detail in the June   
   1 issue of the Physical Review Letters.    
      
      
   Author: Dr. Tony Phillips| Production editor: Dr. Tony Phillips | Credit:   
   Science@NASA   
      
   More Information    
   Honey, I Blew up the Tokamak -- a story from Science@NASA about the   
   Magnetospheric Multiscale Mission (MMS)    
      
   Magnetic Portals Connect Earth to the Sun -- Science@NASA    
      
   MMS home pages:SWRI, NASA   
      
   NASA's Polar Mission -- home page    
      
   MMS Credits: Science team members and instrument development are provided by   
   the University of New Hampshire; Johns Hopkins University Applied Physics   
   Laboratory; NASA Goddard; University of Colorado; Lockheed Martin Advanced   
   Technology Center; Rice University; the University of Iowa; Aerospace   
   Corporation; and the University of California-Los Angeles. International   
   contributions to the MMS instrument suite are provided by the Austrian Academy   
   of Sciences; Sweden's Royal Institute of Technology and Institute of Space   
   Physics; France's Plasma Physics Laboratory and Toulouse Space Center; and   
   Japan's Institute of Space and Astronautical Science.    
      
   MMS is a NASA Science Mission Directorate Heliophysics mission in the Solar   
   Terrestrial Probes Program. MMS is managed by NASA Goddard. Kennedy Space   
   Center is providing launch services   
       
      
   Regards,   
      
   Roger    
   --- timEd/386 1.10.y2k+   
    * Origin: NCS BBS - Houma, LA - (1:3828/7)