Volume 10, Number 13 March 7, 2003

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GRAD PROFILE

Student looks at electrical irregularities in ionosphere

Physics PhD student Roman Makarevitch

Physics PhD student Roman Makarevitch

Photo by Trevor Pritchard

By Trevor Pritchard

When you look up on a wintry night and gaze at the majestic beauty of the northern lights, be assured that Roman Makarevitch is looking along with you.

"What we are doing is called generally space physics," explains Makarevitch, who earned his previous degrees from St. Petersburg State University in Russia.

"Space physics doesn't deal with stars and galaxies, however - it's about the Earth's environment, which is often called the solar-terrestrial environment."

Makarevitch's PhD project explores the plasma instabilities that occur in the Earth's ionosphere, the area of weakly ionized plasma that begins approximately 80 kilometres above the Earth's surface and extends to a height of 1,000 kilometres. Space physicists divide the ionosphere - also known as the "upper atmosphere" - into three separate areas called D, E, and F regions.

Makarevitch's research is focused primarily in the E region, the area of the ionosphere extending from 95 to 130 kilometres in altitude.

"The E region is unique," says Makarevitch , "because very intense electrical currents exist there. These currents can actually influence a lot that can be happening on the ground."

The E region is also where the electrical discharges which cause the aurora borealis - commonly called the northern lights - take place.

The currents in the E region, Makarevitch explains, are caused by forces occurring in the Earth's magnetosphere, a comet-shaped region thousands of kilometres above the Earth's surface in which particles are trapped by the Earth's magnetic field.

"Plasma instabilities are created because we have sources of free energy in the ionosphere, [and] one of these sources is an electric field of magnetospheric origin."

"When you move a charged particle through the magnetosphere, you get an electric field."

But where do these charged particles come from? Particles emanating from the sun come into contact with atoms and molecules in the Earth's atmosphere, says Makarevitch, creating areas of charged ions and electrons which can wreak havoc with radar-based tracking systems.

Radar works by transmitting a short, high-intensity burst of radio waves in all directions. The waves bounce off the intended targets and echo back to the receiver, allowing the velocity of the moving objects to be measured with great accuracy. The ionospheric irregularities Makarevitch has studied can potentially interfere with the radio signal, making airplanes or other objects in the area difficult to track.

These irregularities, according to Makarevitch , can extend up to 100 kilometres in area. "Sometimes the radar sees a huge blob which can't be seen behind. This is important if you're trying to track an airplane with radar or communicate with radar."

Makarevitch hopes his research will circumvent this navigational nightmare. "One of the problems is understanding what are the conditions for the creation of these irregularities. If you can understand [these conditions], you might be able to predict their location and time."

"We study these ionospheric irregularities," says Makarevitch , "using so-called 'coherent scatter radars' such as the SuperDARN radars - the main instrument in my PhD thesis." The Super Dual Auroral Radar Network (SuperDARN) is an international network of radars that monitor the ionospheric plasma. The network consists of nine radars in the northern hemisphere and five in the southern hemisphere.

The University of Saskatchewan is the headquarters for the Canadian component of the SuperDARN program.

Though now employed at Lancaster University in the United Kingdom, Makarevitch still speaks warmly about his experiences at the University of Saskatchewan, in particular regarding his research supervisor, Prof. Sasha Koustov. "Sasha is a great supervisor; he was able to push me almost to the limit. [Working] with him was a great challenge, and I liked that."

Teaching and researching, according to Makarevitch, are two sides of the same coin.

"One of the things that I enjoyed the most at the U of S [was] the teaching - not only marking and lab demonstrations, but real teaching. You have a class and you have to teach it from beginning to end, and I find that very encouraging."


For more information, contact communications.office@usask.ca


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