Dartmouth College SuperDARN Group
Space Plasma Remote Sensing using Ground-based HF Radars
With the help of Dartmouth College students, students and colleagues from three other institutions, Thayer School professor Simon Shepherd constructed a pair of high-frequency backscatter radars in the desert of central Oregon over the Summer and Fall of 2010. These radars are funded by the National Science Foundation (NSF) and are part of an internationally funded global network of radars known as the Super Dual Auroral Radar Network (SuperDARN). There are more than 27 SuperDARN radars currently operating in the northern and southern hemispheres (maps).
During normal operation, pulses of radio waves are transmitted in a beam directed forward of the antenna arrays. The radio signal travels up into the Earth's ionosphere and is partially reflected by irregularities in the plasma that makes up the ionosphere. The reflected (backscattered) signal travels back to the radar where the Doppler shift in the signal is measured. Using the same principle as that used by weather radar to detect motions of the atmosphere, a SuperDARN radar can measure the speed at which plasma is moving. By combing observations from all of the radars in the network, a comprehensive view of the plasma motion in the polar ionospheres can be measured and used in studies of the electromagnetic coupling between the solar wind the Earth's magnetosphere. (more information about SuperDARN radars)