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A University of Iowa researcher wants you to visualize a plate ofspaghetti when you think of the northern lights. That's becauseJack Scudder, UI professor of physics and astronomy, and hiscolleagues have reached a milestone in describing how the northernlights work by way of a process called "magnetic reconnection." The details are contained in a paper published in the journalPhysical Review Letters; however, the process is best imagined asuntangling twisted strands of spaghetti. Diffuse gas-called plasma-flows outward from the sun as the "solarwind" and carries with it magnetic field lines ("spaghetti") fromthe sun. The entanglement between magnetic field lines (spaghetti) from thesun and other field lines (spaghetti) anchored in the Earth's coreoccurs when these field lines are brought together by gusts ofsolar wind. "In the process of smoothing this entanglement, one or more holesare created that now link field lines, with one originating in thesun and the other in the Earth's metallic core," says Scudder. "This linkage allows charged particles to cross a previouslyforbidden boundary that separates the Earth's volume from thesun's. The formation of these inter-connections represents a stressreduction. The aurorae are a byproduct of this change in how the strands ofspaghetti are connected, since with the hole, charged particlesfrom the sun are now allowed access into the atmosphere below theEarth's magnetic shield." One result is the beautiful colors of the northern lights. "Most effects of solar weather that have an earthly influence gainentrance through holes of this type that are in place when a solardisturbance hits," Scudder says. "In this sense the sites ofreconnection are the 'keyholes' for the intrusion of solar weatherinto near Earth space. "After more than 30 years of research, my colleagues and I haveannounced a milestone discovery in astrophysics-the firstexperimentally resolved and unequivocal site of collision-lessmagnetic reconnection, in which magnetic field energy is convertedinto energetic particles," Scudder says. "When this process occurs, previously separated volumes of spacebecome interconnected by magnetic fields, providing new highwaysfor the prompt interchange of high temperature gases." Because magnetic reconnection is thought to occur elsewhere in theuniverse, Scudder and his colleagues are delighted to have observedevidence of a hard-to-see hole. In astronomical terms, the size of a hole is relatively small-about1 kilometer in diameter seen at a distance of 57,000 kilometersfrom the Earth. If magnetic reconnection were occurring on thesurface of the sun, at another star, or at a planet in anothersolar system, scientists would never be able to see it, Scuddersays. Consequently, Scudder's work is all the more important because itserves to "bench test," or prove, an astrophysical process thatmankind will never be able to directly corroborate in deep space. In addition to being small, the hole Scudder observed was inconstant motion. Because the hole was in an unknown state of motion relative to thespacecraft, it could have been traversed many times previouslywithout having been detected. To correct for this situation,researchers developed new techniques to reduce the time intervalbetween "snapshots" by a factor of 11 using the same detector andwithout flying a new detector. "This 'trick' is like having access to a microscope for the firsttime to re-examine data that was thought to have been acquired tooslowly to find these holes. Resolving these holes in magnetic fields is somewhat similar tolooking at stagnant water through a microscope for the first timeand seeing the writhing molecular behavior that was only suspectedpreviously," he says. Scudder and his colleagues were able to observe the magneticreconnection site in space by using data from NASA's Polarspacecraft and its Hydra, MFE and EFI experiments. Scudder says theprocess he observed is active not just in creating the northernlights, but many other astronomical phenomena as well. "The experimental documentation of the physical process thatenables this phenomenon provides the first support of theprevailing theories for explaining the production of solar flares,x-rays from black holes, as well as the causes of the aurorae thatbrilliantly light up the polar skies," he says. The manner in which Scudder and his associates made the landmarkobservation involved five different comparisons across threeindependent detectors to reinforce the detection, similar to theteamwork involved in professional sports. As part of NASA's Polar/Hydra program at the UI, data from threeseparate experiments were shown to reproduce the extreme signaturespredicted by computer models of the process. These signatures were so unusual that nothing approaching theirextremes had been recorded in 50 years of space research. Using thelargest computer resources at NASA, the National ScienceFoundation, and the U.S. Department of Energy, the referencecomputer models solved six trillion equations of motion in order topredict the observations for the three experiments. By showing scientists what combinations of observations can helpidentify these regions, Scudder's work will save time and energyfor researchers preparing to explore magnetic reconnection indetail by using NASA's Magnetospheric Multi-Scale (MMS) mission setfor launch in 2014. Scudder's collaborators and co-authors include UI graduate studentsR.D. Holdaway and J.Y. Lopez. His other colleagues are H.Karimabadi and V. Roytershteyn of the University of California, SanDiego; W.S. Daughton of the Los Alamos National Laboratory, N.M.;and C.T. Russell of UCLA. We are high quality suppliers, our products such as China Induction Seal Liner , China Plastic Pump Dispenser for oversee buyer. To know more, please visits Lip Balm Tubes.
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