Unraveling the mysteries of the ionosphere
David Hysell, professor of earth and atmospheric sciences, believes it would be a very bad sign indeed if the average person on the street were talking about his field of expertise—the ionosphere. “If people are suddenly discussing the upper atmosphere, that will mean something has gone terribly wrong with our cell phones or GPS or some other essential service people rely on.”
Many of the invisible signals that enable cell phones, GPS, cable television, weather forecasts, military communications, and surveillance systems pass through the ionosphere on their way to and from orbiting satellites. For these systems to work properly, it is essential to correct for effects caused by passage through this layer of free electrons. Yet, the behavior of the ionosphere is still very much a mystery.
Hysell is working to unravel the mystery.
“As a boy, I guess you could say I was an ‘unsupervised child,’” says Hysell. “I was into model rocketry; I did chemistry experiments in the basement; I was into ham radio.” It was his involvement with ham radio that led Hysell to major in electrical engineering as an undergraduate at Penn State University. “This is no indictment of Penn State,” says Hysell, “but my undergraduate degree showed me just how superficial humanity’s knowledge of things really is. To learn what I wanted to learn I had to go on to grad school, and even there I saw that there is so much we don’t yet know.”
Hysell came to Cornell for his Ph.D., which he earned in the School of Electrical and Computer Engineering in 1992. He then stayed at Cornell for two more years as a post-doctoral researcher with the Space Plasma Physics group. After an eight-year stint in the physics department at Clemson University, Hysell came to back to Cornell in 2002 and joined the faculty of the Department of Earth and Atmospheric Sciences.
“Once I got back to Cornell, the opportunity opened up for me to become the Principal Investigator for the Jicamarca Radio Observatory and I have been doing that for nine years now,” says Hysell. “It is this observatory that has kept me in the field. It really is an amazing thing. It has a Steam Punk feel to it—it is colossally big and has a mad scientist sort of appeal. It was built at a time when you could get something like that funded. It was a very optimistic proposal that said ‘once we get this thing built, then we will figure out how to use all the data.’”
And that is exactly what Hysell is doing—figuring out how to use all the data. “The ionosphere is a spectacularly complicated medium,” says Hysell. “It looks different from every angle. Scientifically, it is great because it is so complicated and so rewarding. I get to feed my intellectual side because I am exploring some really basic scientific questions and at the same time my work has immediate practical applications.”
Much of the early interest in the ionosphere was driven by NASA and the Department of Defense. They were flying their vehicles through an environment they did not know much about. And then, more and more of the systems humans use to communicate began to pass through the ionosphere, and understanding its properties and behavior became even more essential. The ionosphere has its own ‘weather,’ but it is not the same sort of weather we experience at the Earth’s surface. The climate and weather in the ionosphere are fluctuations in energy and electron concentrations driven by Earth’s response to emissions from the sun.
The stunning increase in computing power over the past few years has enabled Hysell and other researchers to use the data collected at Jicamarca to begin to model the ionosphere. “This system is so complex, that today’s computers are still inadequate,” says Hysell, “but they do now allow us to keep track of a billion particles through code. We are starting to be able to measure state parameters and we are beginning to get a grip on how the most important variables behave normally.”
Hysell believes the day is coming soon when we will be able to produce accurate forecasts of ionospheric weather. “Using the data from Jicamarca and comparing our predictions with observed reality, we are slowly getting to a good model of what goes on in the ionosphere,” says Hysell. “Our goal is to safeguard against outages of services people rely on, and that day is getting closer.” If David Hysell is successful in his goal, then the average person will continue to remain blissfully ignorant of the existence of the ionosphere and space weather.