Posted on: Thursday, June 3, 2004

UH team maps sun's 'dark energy'

By Timothy Hurley
Advertiser Staff Writer

University of Hawai'i scientists today announced they have created a map of the elusive magnetic field in the sun's outer atmosphere, a discovery that could lead to better forecasting of troublesome solar flares and offers greater insight into the way the universe works.

The results of UH scientists Haosheng Lin, Jeff Kuhn and Roy Coulter were presented this morning at an American Astronomical Society meeting in Denver.

The sun's magnetic fields have been measured on the visible surface of the sun for decades, and astronomers have been aware of far-reaching extent of these fields in our universe for a long time. But until now scientists were unable to observe this so-called "dark energy" emanating through the faint outer region of the sun's atmosphere called the corona.

UH scientists, working on top of Haleakala, invented a unique solar telescope and were able to "see" the corona's magnetic fields while working with a highly sensitive imaging infrared spectropolarimeter.

With the naked eye, the corona is visible only during a total eclipse of the sun.

"What we did is create an artificial eclipse inside the telescope," Lin said yesterday from Denver.

Lin said the ability to map the corona's magnetic fields will, among other things, advance the field of space-weather prediction. These invisible fields are responsible for virtually all of the sun's explosive and dynamic phenomena and they play a major role in causing the variations in the amount and kinds of solar radiation that affects the Earth's magnetosphere, ionosphere and, ultimately, its climate.

Last year solar flares and storms knocked out two Japanese satellites as well as power on part of the Swedish power grid. Astronauts could also use a better warning system for their safety in space, Lin said.

Lin said the project's initial "magnetogram" is only the beginning. He said he wants to create an even bigger telescope on Haleakala that will allow scientists to capture greater detail and allow modelers to improve the understanding of how the corona works.

Rolf Kudritzki, director of the UH Institute for Astronomy, said the results are made possible in part because of the excellent solar observation conditions on Haleakala.

Haleakala has been chosen by the National Solar Observatory as one of three candidate sites for the $160 million Advanced Technology Solar Telescope, which will be one of the world's largest ground-based solar optical observatories. Lin said the proposed telescope can be adapted to produce quality corona magnetograms.

Reach Timothy Hurley at (808) 244-4880 or thurley@honoluluadvertiser.com.