X-Ray imager with wide field of view provides detection capabilities for solar wind emissions.
Solar winds are known for powering dangerous space weather events near Earth, which, in turn, endangers space assets. So a large interdisciplinary group of researchers led by NASA has set out to create a wide-field-of-view soft X-ray imager capable of detecting the soft X-ray emissions produced whenever the solar wind encounters neutral gas.
The imager centres on “Lobster-Eye optics,” and was inspired by simulations created about a decade ago by Tom Cravens and Ina Robertson at the University of Kansas, both of whom are now involved in this work, which demonstrated that the interaction between the solar wind and the residual atmosphere in Earth’s magnetosphere could be imaged in soft X-rays.
Lobster-Eye optics refers to an optical element used to focus soft X-rays, developed by the University of Leicester in the UK and Photonis Corp. in France and inspired by the eyes of the crustacean. The optical element consists of an array of very small square glass pores, 20 microns on a side curved like a section of a sphere, with a radius of 75cm. “Our imager operates on the same principle as the lobster eye, which is how it got its name, by focusing soft X-ray photons onto a plane located at half the radius of the sphere,” explained Michael R. Collier, an astrophysicist working for NASA’s Goddard Space Flight Center.
A wide-field-of view imager in space takes astronomers a step closer towards global solar wind and magnetosphere imaging capabilities. Globally imaging the solar wind’s interaction with the Earth’s magnetosphere will enable tracking the flow of energy and momentum into the atmosphere. “Because all of the energy that powers dangerous space weather events near Earth comes from solar wind, this capability allows us to better protect our space assets, particularly geosynchronous spacecraft, such as those that carry cell phone signals,” Collier added.
The technique is also easily adapted to nanosatellites such as CubeSats, which could enable low-cost missions with a high science return.