Auroral Processes

Auroral Processes, and the related magnetospheric changes, are areas of high priority for research by the Solar Terrestrial Physics community in Canada and internationally (Jean-Pierre St-Maurice, Sasha Koustov, Glenn Hussey. Kathryn McWilliams and George Sofko(Emeritus)). The term "space weather" has been developed to describe the periods of calm and storm in "geospace" near the earth (above 100 km), due to processes that occur on the sun. Understanding and eventual prediction of these storms is desirable, as their effects upon space vehicles and ground based energy distribution systems are serious. A number of communications satellites have been lost (two $100 million Canadian ANIK satellites in one day in January, 1994) due to "geospace" storms, and lost economic activity totalling billions of dollars was suffered by Quebec and the northeastern US during the power blackout of March, 1989.

In ISAS, these processes have been studied for many years, using ground-based optical and radar systems and satellites which sample the magnetospheric space or "geospace" in addition to observing the aurora from above and below.


The major project of these scientists is the highly successful international Super Dual Auroral Radar Network (SuperDARN)(George Sofko (Emeritus) et al), in which pairs of HF (high-frequency) Doppler radars are used to measure, for both hemispheres, the ionospheric velocity and electric field patterns, and also the voltage map. In principle, each radar pair can measure a region of the ionosphere over 3 million square kilometers in size, and can do this for 24 hours each day. These fields-of-view (FOVs) are so large that the radars are ideal instruments for joint studies with satellites which are at very high altitudes but sample along the same magnetic field lines. These stretch from the distant magneto-sphere to the ionosphere. Large and small-scale tornado-like vortex motions, located in the ionospheric flow patterns, are correlated with solar wind fluctuations obtained by satellites located about 1.5 million kilometers from the earth. In January 2002, there were 15 operating radars, 9 in the northern and 6 in the southern hemisphere. Substantial funding has been provided for SuperDARN by Canada, the United States, France, Great Britain, Japan, South Africa, Australia, and Italy. The ISAS team controls the Saskatoon, Prince George, Rankin Inlet, Inuvik and Clyde River radars, whose partners are the US-run radars at Kapuskasing, Ontario, and Kodiak, Alaska, respectively.

To find out more about SuperDARN, go to

Ionospheric Motion

Jean-Pierre St-Maurice, Sasha Koustov, Glenn Hussey, and Kathryn McWilliams use radars to study motions in the earth's ionosphere, the region above 100 km in which auroras occur. These motions are caused by electric fields generated far above the ionosphere when the solar wind blows against the earth's magnetosphere. As a result, by studying the ionospheric motions, we can learn a great deal about the transfer of energy to the earth's magnetosphere from the sun via the solar wind.

VHF Radars

The group also uses VHF (very high frequency) radars for studies of the lower ionospheric E-region, located about 100-120 km above the surface (Glenn Hussey, Alan Manson(Emeritus)). These radars are used to study the very complex plasma physics in this region and are also very useful for auroral substorm studies. During substorms, currents of over 10 million Amperes, driven by voltages of 100,000 Volts or more, can flow in the ionosphere, generating power equivalent to that from ten thousand 100 MegaWatt electrical power stations on the earth!