November 29, 2012
New Instruments Helps Decode Mystery Of Auroras
Lee Rannals for redOrbit.com — Your Universe Online
Space-weather researchers joined forces to design and build NORUSCA II in order to help expand the understanding of auroras and other atmospheric events.NORUSCA II is a new camera with the capabilities of simultaneously imaging multiple spectral bands. The camera was tested at the Kjell Henriksen Observatory (KHO) in Svalbard, Norway.
The camera produced the first-ever hyper spectral images of auroras and may have already revealed some previously unknown atmospheric phenomenon.
Auroras are created when charged particles from the Sun penetrate Earth's magnetic field, displaying a spectacular light show in the sky. For researchers to study this phenomenon, they have to look at specific bands, or a small portion of the spectrum, through a series of filters to block out unwanted wavelengths.
The new camera is capable of studying the Northern Lights without any moving parts, using its advanced optics to switch among all of its 41 separate optical bands in a matter of microseconds.
"A standard filter wheel camera that typically uses six interference filters will not be able to spin the wheel fast enough compared to the NORUSCA II camera," Fred Sigernes of the University Centre in Svalbard (UNIS), Norway, said in a statement. "This makes the new hyperspectral capability particularly useful for spectroscopy, because it can detect specific atmospheric constituents by their unique fingerprint, or wavelengths, in the light they emit."
The spectral signatures can reveal subtle changes in atmospheric behavior, such as the ionization of gases during auroras. This form of multispectral imaging enables scientists to better classify auroras from background sky emissions and study the clusters in the atmosphere.
A major solar flare shot off from the sun back on January 24, 2012, slamming a Coronal Mass Ejection into Earth's magnetic field, producing picturesque auroras.
The researchers were able to use NORUSCA II to image the aurora through a layer of low altitude clouds. It also helped reveal a very faint wave pattern of unknown origin in the lower atmosphere.
The wave pattern resembles "airglow," which is a natural emission of light by Earth's atmosphere and chemical reactions. Its appearance with the aurora suggests it may also be caused by a previously unknown source.
"After the January CME, we think we saw an auroral-generated wave interaction with airglow," Sigernes said in a statement.
This occurrence would be an entirely new phenomenon and could be the first time airglow has been associated with auroras.
"Our new all-sky camera opens up new frontiers of discovery and will help in the detection of auroras and the understanding of how our Sun impacts the atmosphere here on Earth. Additional development and commissioning will also hopefully verify our intriguing first results," Sigernes said.