Is a space tsunami the cause of a third Van Allen belt?
Researchers at the University of Alberta have come up with a solution to a problem that has been puzzling physicists and astronomers since 2013.
It was then that NASA sent its two Van Allen Probes into the region of space surrounding the Earth called the Van Allen radiation belts in order to gather more information on these phenomena. For years, scientists believed that two Van Allen belts existed within Earth’s magnetosphere -that region of space where the Earth’s magnetic field affects the movement of charged electrons and protons.
But the NASA probes were able to observe the temporary presence of a third belt, which lasted for two weeks before being washed away into space.
What caused the third Van Allen belt to emerge and why? “We have discovered a very elegant explanation for the dynamics of the third belt,” says Ian Mann, physics professor and lead author of a new study published in the journal Nature Physics. “Our results show a remarkable simplicity in belt response once the dominant processes are accurately specified.”
Using data retrieved from the NASA probes, Mann’s team discovered that intense low frequency plasma waves are periodically washing over the whole of the Earth’s magnetosphere, causing the outer part of the Van Allen belts to temporarily break off and form a third outermost ring of charged particles, only to later be dispersed into space. The research team likens the effect to a “space tsunami” working in wave-like fashion across the region surrounding the Earth.
“Remarkably, we observed huge plasma waves,” says Mann, who is also co-investigator on the NASA Van Allen Probes mission. “Rather like a space tsunami, they slosh the radiation belts around and very rapidly wash away the outer part of the belt, explaining the structure of the enigmatic third radiation belt.”
Study of the Van Allen belts is particularly important since the radiation within them can interact with materials such as satellite components as well as solar cells and sensors on spacecraft. The highly charged particles can play havoc with such delicate mechanisms which are crucial to modern telecommunications. The International Living with a Star Program works as a cooperative venture among several international space agencies in order to learn more about the effects of space radiation and space-based weather on terrestrial communications systems. The group estimates that damage, both to satellites and to power grids here on Earth, caused by high-impact space weather storms could be as high as $2 trillion (USD). In response, both the United States and Europe have recently established strategies for monitoring space weather storms so as to mitigate their effects on power and telecommunication systems.
“Space radiation poses a threat to the operation of the satellite infrastructure upon which our twenty-first century technological society relies,” says Mann. “Understanding how such radiation is energized and lost is one of the biggest challenges for space research.”
Due to its northerly positioning, Canada is thought to be highly susceptible to the effects of space storms. In March of 1989, a powerful solar flare caused safety devices in Quebec’s power grid to trip and kept the entire province without power for nine hours, and in August of that same year, a similar solar flare knocked out computer systems used by the Toronto Stock Exchange, causing an immediate halt to trading.