A ground network for observation of the aurora borealis

This magnificent view of the northern lights was taken in Finland by © Jouni Joussila

This magnificent view of the northern lights was taken in Finland by © Jouni Joussila.

CANOPUS, the ground-based auroral observation network, was set up in Canada in 989. Under an international agreement, International Living With a Star, which a number of countries are joining, including Canada, the U.S., Japan, Russia, and the European Space Agency (ESA), CANOPUS will be getting a second wind. This agreement will promote use of the Canadian network to study the phenomena at work within the magnetosphere of the Earth, such as the aurora borealis, to evaluate their impact on Canadian infrastructure and activities.

Originally set up under the International Solar-Terrestrial Physics Program, CANOPUS now consists of 3 stations (soon 6) across Canada, each equipped with a magnetometer, the essential instrument for studying the magnetosphere. Four are also equipped with photometers. These are very useful for research on the aurora since they enable quantitative information on the aurora borealis to be collected at various wavelengths.

Aurora photographed in Finland by © Jouni Joussila.

Aurora photographed in Finland by © Jouni Joussila.

A little science

The aurora borealis remains an enigma for the experts. They know, however, that the northern lights are caused by the solar wind blowing toward the Earth, which consists of ionized particles. To a large extent, these are filtered out by the Earth's magnetosphere. Some electrons do however manage to slip through the mesh and generate a yellow, green or red glow if they strike oxygen atoms in the atmosphere. If they collide with nitrogen molecules, on the other hand, the light produced will be blue or violet.

CANOPUS will be used to study the formation of the aurora borealis, but in reverse order, somewhat as though we were to read the end of a story before finding out how it starts. We know that solar wind and storms are the cause of the aurora borealis. These are the phenomena that trigger the process. But what happens between the time a solar storm occurs and the time the aurora becomes visible? Scientists hope to discover the chronological sequence of events by working backwards.

A complementary network

Location of the 16 stations in the CANOPUS network.

Location of the 6 stations in the CANOPUS network.

The advantage of a ground-based network like CANOPUS is that it complements the satellite-based data. Where CANOPUS gives an overview of the magnetosphere, a satellite can observe a particular area of it. Together, the ground and space data are of great interest to scientists.

The network is used in conjunction with the European Space Agency's Cluster II satellite and will be part of a joint mission with the THEMIS satellite satellite launched by NASA in 007.