March 20, 2014
New Zebra-Striped Structure Discovered In Van Allen Radiation Belt
[ Watch the Video: Van Allen Probes See Zebra Stripes ]
redOrbit Staff & Wire Reports - Your Universe Online
Data from NASA’s twin Van Allen Probes has led to the discovery of a new, potentially dangerous zebra-striped structure located in Earth’s inner radiation belt, according to new research appearing in Wednesday’s edition of the journal Nature.
In the paper, lead author Aleksandr Ukhorskiy of the Johns Hopkins Applied Physics Laboratory (APL) and his colleagues explain that the Van Allen Probes Ion Composition Experiment (RBSPICE) located the persistent structure, which was comprised of highly energized electrons that could endanger humans in space.
In addition, the zebra-striped formation could also disrupt low-earth navigation and communication satellites, officials from the US space agency explained. The structure was produced by the planet’s slow rotation, which experts had previously believed was unable to impact the motion of high-speed radiation belt particles.
“It is because of the unprecedented resolution of our energetic particle experiment, RBSPICE, that we now understand that the inner belt electrons are, in fact, always organized in zebra patterns,” said Ukhorskiy. “Furthermore, our modeling clearly identifies Earth's rotation as the mechanism creating these patterns. It is truly humbling, as a theoretician, to see how quickly new data can change our understanding of physical properties.”
The tilt in Earth’s magnetic field axis causes its rotation to generate a weak, oscillating electric field permeating throughout the entire inner radiation belt, Ukhorskiy explained. He compared the electron populations of the inner belt to a viscous fluid, and said that the global operations would slowly stretch and fold like taffy, resulting in the striped pattern that extends from above the atmosphere to approximately 8,000 miles above the Earth’s surface.
According to NASA officials, the Van Allen radiation belts “are dynamic doughnut-shaped regions” that surround our planet high above the atmosphere. They are comprised of high-energy electrons and ions that are trapped by the Earth’s magnetic field, and solar activity affects the radiation levels throughout the belts.
These solar storms and related activity originating from the sun can ebb and flow, the agency added. Radiation levels can dramatically increase during active conditions, which can generate hazardous space weather conditions that could harm orbiting spacecraft and place astronauts in danger. The goal of the Van Allen Probes is to better understand exactly how and why the radiation levels in these belts change with time.
“These findings could have implications for those who model space weather and those who design and operate navigation and communication satellites as well as spacecraft used for national security,” said study co-author and New Jersey Institute of Technology physics professor Louis Lanzerotti.
“It is amazing how Earth's space environment, including the radiation belts, continue to surprise us even after we have studied them for over 50 years,” he added. “Our understanding of the complex structures of the belts, and the processes behind the belts' behaviors, continues to grow, all of which contribute to the eventual goal of providing accurate space weather modeling and helping designers to build communication systems and spacecraft that can withstand the highly energized particles in earth's radiation belt.”