For many geophysical and atmospheric observations, scientists lie in wait for storms and other naturally occurring phenomena. But high-frequency (HF) ionospheric heaters, like the one set to start up this spring at the Arecibo Observatory in Puerto Rico, can turn the ionosphere into a plasma-physics laboratory.
The HF heater is used to deposit energy into the ionosphere in a controlled way; scientists observe the response to learn about the ionosphere and neutral upper atmosphere. For example, heating a bit of plasma and then watching how it cools takes about 15 minutes, says Sixto González, Arecibo’s director for space and atmospheric sciences. The process mimics what happens in the ionosphere during sunrise, “so I could heat and let cool, over and over. That’s 30 or 40 sunrises in a night,” says González. He did such studies with Arecibo’s last HF heater, which was wiped out in 1998 by Hurricane Georges.
To...
