Above about 100 km altitude, the atmospheric gas becomes quite rarified, and a plasma of electrically charged particles exists. This is a natural part of the Earth’s upper atmosphere, and the electrically charged layer is called the ionosphere. The motion of the charged particles in the ionosphere and throughout the solar system is controlled primarily by electromagnetic forces. Forces on the charged particles in the ionosphere and in near-Earth space are imposed by the fast flowing solar wind plasma and the interplanetary magnetic field, which emanate from the Sun out through the solar system.
Why Is SuperDARN Essential for Understanding Space Weather?
Similar to how atmospheric weather is driven by high and low pressure systems, space weather is driven by high and low voltage systems. The SuperDARN circulation/voltage maps are essential input to solar system science.
A plasma circulation map produced by the SuperDARN network. The contours indicate voltage magnitude, which describe the plasma flow speed. This is similar to how pressure contours indicate wind speed on weather maps.
The ultimate goal is to produce a unified space weather model that, given space weather conditions at the Sun, can predict what will happen in the Earth’s atmosphere (including plasma circulation, auroral displays, and changes to GPS signal quality) and even down into the ground where electrical currents are induced.
Space science is currently in its infancy, and researchers worldwide are studying parts of the system. The final model must be capable of dealing with processes as big as the solar system and as small as an electron at the same time. The global nature of SuperDARN observations are essential for understanding how electromagnetic forces in space affect the Earth on a global scale, and to understanding the localized plasma physics in the ionosphere.