Launched only a short time ago, NASA’s mission to explore the Earth’s Van Allen radiation belts has revealed a wealth of data about this recently-discovered phenomenon.
In general, if you ask the average guy on the street “What is the Van Allen Belt?” then you’ll probably get a blank stare. If you ask them “What is the magnetic field?” then you’re likely to get more of an answer, something about how it surrounds the Earth, with magnetic lines of force that leave one of the Earth’s poles, loops out into space for a bit before rejoining the planet at the other pole.
For those of a more scholarly persuasion you might even get an explanation of the Aurora Borealis, the amazing light show that results when charged particles from the Sun impact and interact with the magnetic field. The Van Allen belt (put simply) is a large area of charged particles that have been trapped by the Earth’s magnetic field. Satellites that operate in this region normally have to have extra shielding to protect them from the extra radiation.
NASA launched the Van Allen Probes (formerly known as the Radiation Storm Belt Probes) mission at the end of August to collect information about this region of space. Since then a surprising amount of data has been recorded for a mission that is only three months into its two-year run – although the probes carry enough consumables for another two years beyond that.
At the end of October we saw quite a large amount of solar activity; there were a couple of strong solar flares and coronal mass ejections (that we’ve previously covered). Researchers looking at the data from this period saw strongly dynamic activity in the radiation belts instead of the largely placid field that they were expecting- indicating that solar activity has a much greater effect in the mechanisms behind the belt than previously thought. The probes were quite literally in the right place at the right time to record the influence of the large amount of solar activity in October.
It is hoped that as the behaviour of the region is studied in detail, future generations of spacecraft will benefit from the research as new methods of radiation shielding are developed.