The polar wind or plasma fountain is a permanent outflow of plasma from the polar regions of Earth's magnetosphere.[2]: 29 Conceptually similar to the solar wind, it is one of several mechanisms for the outflow of ionized particles. Ions accelerated by a polarization electric field known as an ambipolar electric field is believed to be the primary cause of polar wind. Similar processes operate on other planets.[3]
^Schunk, R. W.; Nagy, Andrew (2000). Ionospheres: physics, plasma physics, and chemistry. Cambridge atmospheric and space science series. New York: Cambridge University Press. ISBN978-0-521-63237-9.