This artist's concept shows NASA's Voyager 1 spacecraft in a new region at the edge of our solar system where the magnetic field lines generated by our sun are piling up and intensifying. Voyager 1 is in an area scientists are calling the depletion region where the magnetic field acts as a kind of "magnetic highway." In this region, energetic ions from inside the heliosphere, the magnetic bubble that the sun blows around itself, escape out, and energetic ions from interstellar space zoom in. (To learn more about how this region acts as a magnetic highway, see PIA16486.) The depletion region is the outermost known layer of the heliosphere.
Magnetic field lines form a spiral around the solar system because of the rotation of the sun (see PIA15179), and at the edge of the solar system they form roughly parallel lines. At the end of 2004, Voyager 1 passed the termination shock, where the solar wind abruptly slowed down and compressed, and the intensity of the magnetic field tripled as the distance between magnetic field lines decreased by one-third. By mid-2010, Voyager entered a stagnation region where the wind slowed almost to a stop and the magnetic field intensity increased twice again as the magnetic field lines were pressed closer together. In August 2012, Voyager 1 entered the outermost known layer where the depletion of energetic ions allowed the field lines to compress even closer together. Scientists believe the field lines are piling up because an interstellar wind outside is pushing back.
Illustration credit: NASA/JPL-Caltech
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