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Release: May 31, 2002

UI researcher wins $700,000 NASA grant in international competition

A University of Iowa researcher has received a $700,000 NASA grant to use the International Space Station (ISS) to study the motion of waves through crystalline lattices -- the patterns of regularly arranged atoms that comprise such materials as iron.

John Goree, professor of physics and astronomy in the UI College of Liberal Arts and Sciences and project principal investigator, is preparing a new experiment, "Optically-excited waves in 3-D dusty plasmas," for study aboard the ISS sometime after 2006.

His grant and a related proposal (both written by Goree and professor Alexander Piel of the University of Kiel, Germany) were ranked by peers as first and second among some 117 proposals submitted by scientists from around the world. Goree says that "most competitions to do space experiments under weightlessness conditions are national in scope, but this was international. According to NASA it was the first-ever such competition for the physical sciences that was not at the national level." NASA and space agencies from Europe, Japan, and Canada all cooperated in this event.

The ISS experiment may provide scientists with a better understanding of how a crystalline lattice conducts sound waves produced by a supersonic disturbance, similar to the sonic shock created by a fighter jet moving through the air.

Goree says that ordinarily, it is impractical to watch tiny atoms move about inside a crystal -- for example, in a piece of metal -- as a sonic boom passes by, so he devised an alternative. Instead of atoms, he uses plastic spheres that are tiny (about one-tenth the size of a human hair), but big enough to view through a microscope as they move about. The spheres have an electric charge that helps them arrange themselves in a regular pattern, like atoms in a crystal. This kind of crystal is called a "dusty plasma." The problem, Goree says, is that these plastic balls are compressed by gravity and fall down when the experiment is done on Earth, so he proposes doing the experiment in the weightlessness conditions of space.

Using a laser beam to excite the sonic boom in the crystal in space, he will watch the motion of his "atoms" on videos that will be flown back to Earth from the space station. The entire experiment will be videotape-recorded through the vacuum chamber's glass windows, and the videotapes analyzed at the UI.

Earlier this year, Goree's Plasma Crystal Experiment became the first physical sciences experiment to be conducted aboard the ISS. The purpose was to observe how crystals form in space, free of Earth's crushing gravity.

Co-investigators on the interdisciplinary experiments include professor Amitava Bhattacharjee and Zhiwei Ma, UI associate research scientist, of the UI department of physics and astronomy and researchers from Los Alamos National Laboratories; the University of Kiel, Germany; the University of Tromso, Norway; and Dalian University of Technology, China.