NASA`s IBEX reveals cosmic roadmap to galactic magnetic field

Washington: NASA `s Interstellar Boundary Explorer (IBEX) has helped paint picture of the magnetic system beyond the solar wind. The data sets show a magnetic field that is nearly perpendicular to the motion of our solar system through the galaxy. In addition to shedding light on our cosmic neighborhood, the results offer an explanation for a decades-old mystery on why we measure more incoming high-energy cosmic rays on one side of the sun than on the other. IBEX, which orbits Earth, studies these regions from afar. The spacecraft detects energetic neutral atoms that form from interactions at the heliosphere`s boundaries - an area that holds fascinating clues to what lies beyond. These interactions are dominated by electromagnetic forces. The incoming particles from the galaxy are made up of negatively-charged electrons, positively-charged atoms called ions, neutral particles and dust. Charged particles are forced to travel along the magnetic field lines that snake throughout space. Sometimes, a charged particle collides with a neutral atom at the outskirts of the heliosphere and captures an electron from the neutral atom. After stealing the electron, the charged particle becomes electrically neutral and speeds off in a straight line. To see if the IBEX data related to the cosmic ray observations, Schwadron used IBEX data to build a computer model of what the interplanetary magnetic field would look like around the heliosphere. Without the heliosphere, the field lines would be straight and parallel.

With this model in hand, he simulated how the heliosphere would affect the cosmic rays. He assumed that the rays came in to the heliosphere evenly from everywhere in space, but allowed them to be warped based on the local magnetic geometry. The simulations showed a non-uniform distribution of cosmic ray particles that jibed well with the unevenness seen in observations. The study has been published in the journal Science Express.