Earth ’s magnetic field playact as a shield against dangerous cosmic rays and knock-down solar winds . Some of the particles hitting the magnetic field become at bay and forge orotund swarm of charged atom , mostly electrons and protons , coiffure in radiation belts , known as the Van Allen belts .
To protect artificial satellite and blank space missions , it is significant to understand on the nose how the bash are shaped and how corpuscle in them move . NASA has two probes study the belts , and the belated results have been published in theJournal of Geophysical Research .
The belt were discovered in the 1950s and they were render as two concentric donut , a modest stable one between 1,000 and 6,000 kilometers ( 600 and 3,700 miles)and a large deviate one between 13,000 and 60,000 kilometer ( 8,100 and 37,300 miles ) . But that no longer seems to be the case .
“ The shape of the belt is actually quite dissimilar depending on what case of electron you ’re looking at , ” said Geoff Reeves , lead writer of the report , in astatement . “ Electrons at different energy levels are distribute otherwise in these regions . ”
1 . The traditional flick of the radiation belts include a larger , more dynamic out belted ammunition and a smaller , more stable inner belt 2 . Highest energy electrons form the outer belt only . 3 . The lowest energy electron have an inner belt much large than in the traditional mental picture , amplify into the region that has long been considered part of the empty expansion slot region . The out belt is diminish and does n’t expand as far . 4 . During geomagnetic storms , the empty region between the two belts can occupy in completely with down - energy electrons . NASA Goddard / Duberstein
The new analysis focuses on negatron dispersion through the belts . NASA’sVan Allen Probeswere able to appraise electrons at hundreds of different energies and map how the belts deepen .
consort to the work , low - energy electrons form a thicker interior belt while the outer belt remain very thin . On the other deal , the highest DOE electron are only found on the forbidden belt and they can not penetrate the magnetic force field to populate an inner knock .
But something peculiar can happen during geomagnetic storms . The belt are expanded and compressed , and when considering only lower vim electrons , the time slot between the two knock disappear altogether .
The changes in the belts due to space atmospheric condition are unpredictable so far , but the Van Allen Probes are the right peter to finally see the detailed effect of solar storms on the magnetic playing field .
“ When we reckon across a broad range of muscularity , we commence to see some consistencies in violent storm dynamic , ” said Reeves . “ The electron reception at dissimilar vim layer differs in the details , but there is some common deportment . For lesson , we bump that electrons fade from the slot neighborhood chop-chop after a geomagnetic storm , but the location of the time slot realm depends on the energy of the negatron . ”
By modeling the organic evolution of the belts during calm and active periods , scientist will be able to protect both satellites and future cosmonaut during gamy - altitude missions .
