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Posted 02/18/03, by Tamara Steinert
Unmanned rocket gathers data about Northern Lights
Millions of people have seen the laboratory where Jim LaBelle carried out his latest research, but very few have visited it. In fact, he's never even been there himself. That's because the physics professor chose the natural phenomenon known as the aurora borealis, or Northern Lights, as the environment for his latest experiment.
LaBelle, a plasma physicist, recently participated in the launch of an unmanned NASA rocket more than 230 miles above Alaska's Poker Flat Research Range into the aurora. Mounted on the 50-foot rocket was a special instrument designed, fabricated and calibrated by LaBelle, staff engineer Hank Harjes and graduate student Marilia Samara to gather information about high-frequency waves and turbulence in the aurora. The researchers hope to use data collected during the flight to verify principles of plasma physics. Eventually this research could help scientists learn how to predict space weather in the same way meteorologists do earthly weather.
"The aurora, sometimes described as 'nature's TV,' are caused by electrons fired into the atmosphere from above, analogous to a TV set in which electrons are fired at the TV screen, yielding an image. In nature, the atmosphere is the TV screen, and the northern lights are the image," LaBelle explained.
At altitudes where the aurora occurs, 100-600 kilometers above the earth, the atmosphere is dominated by plasma. In physics, plasma is a gas composed of electrically charged particles. While all gases are affected by natural forces such as pressure and gravity, the electrical charge in a plasma makes it respond to magnetic and electrical forces as well. Plasmas are found throughout the universe and remain a topic of outstanding interest and research for scientists.
"The aurora represents a relatively accessible plasma, so sending this rocket up and gathering this data is like having a natural laboratory where we can test plasma theories that apply elsewhere in the universe," LaBelle said.
It took more than two years to prepare for the 10-minute flight over Alaska. When everything was set to go, the researchers found themselves at the mercy of Mother Nature, waiting for good launch conditions.
"We needed an energetic aurora that was directly over the path of the rocket, because the rocket's path is fixed. We had to wait until the aurora was in the right place," LaBelle said. Finally, on the sixth night, conditions were ideal to launch the rocket, a two-stage Terrier-Black Brant IX.
Although many rockets have been launched into the aurora, the instrument created by LaBelle, Harjes and Samara was able to capture an unprecedented amount of data about high-frequency waves in the ionosphere, according to LaBelle.
"We were collecting data from high-frequency waves that slosh back and forth millions of times per second, which means the instrument had to be able to collect millions of data points per second," he explained. "We wanted to measure enough characteristics of the waves so that we could see if they matched with those predicted by plasma physics theory."
More than 2 years of preparation went into preparing for the launch, but LaBelle said the real adventure is still to come. "The work for us is just beginning. The excitement really starts when we get the data," he said, noting that the researchers could have preliminary analysis of the data as soon as a month.
- Tamara Steinert
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