Lightning Radio Emissions
Did you know that here in Atlanta we can easily observe lightning from almost anywhere on the planet? This is because lightning releases intense low frequency radio waves that propagate globally, reflecting from an upper atmospheric electrically charged layer known as the ionosphere.
Global Field Experiments
The wondrous Earth is our laboratory, and the low frequency radio wave is our microscope to understand the her natural electricity. We enjoy travelling to conduct our experiments. We operate receiver sites all over and bring the data back to analyze using advanced signal processing.
Radio Receiver Design
We build hardware, too! We design our own radio reciever, the most sensitive radio receivers you can find in this band, capable of detecting even weak lightning activity from thousands of miles away. Hands-on work is shared as a team effort by the whole group.
Generating low frequency waves for global communications and navigation ordinarily requires enormous antennas covering thousands of acres. We are rethinking and redefining the antenna with novel approaches, with potential implications to radars and other electromagnetic applications.
Navigation and Comms
Because low frequency waves travel globally, they have practical uses. Long before GPS existed, engineers used low frequency waves broadcast from radio stations to determine location anywhere on the planet. And various navies have been using low frequency waves to communicate with submarines across an entire ocean.
Low frequency waves play an important role in space physics. There are bands of intense radiation (originally from the sun) that surround the Earth, which bombard and destroy satellite electronics. It turns out that low frequency waves may hold the key to understanding how these radiation belts form and evolve.
Maybe you think of TV screens, but most of the universe, including the Earth's surrounding space environment, is comprised of plasma. And when radio waves, particularly at low frequencies, propagate through plasmas, really interesting things happen. We merge observations with theoretical models.
High Altitude Ballooning
Why confine ourselves to the ground? We lead an undergraduate team of researchers building high-altitude (100,000 ft) balloons equipped with sensors (cameras, x-ray, electromagnetic), to study lightning and other upper atmospheric phenomena from above. Students earn credit and can stay on the team for years.