„Birkeland-áramok” változatai közötti eltérés

A Birkeland-áramok gyakran mutatnak sodrott kötélhez hasonló mágneses struktúrát. Az [[áramerősség]]ük eléri az 1 millió ampert. Ezzel fel tudják melegíteni a felső atmoszférát, ami az [[alacsony Föld körüli pálya|alacsony pályán keringő]] [[műhold]]ak számára erősebb légköri fékeződést okoz.

Auroral Birkeland currents can carry about 1 million amperes (Germany, et al.). They can heat up the upper atmosphere which results in increased drag on low-altitude satellites. Birkeland currents can also be created in the laboratory with multiterawatt pulsed power generators. See Fig. 2. The resulting cross-section pattern indicates a hollow beam of electron in the form of a circle of vortices, a formation called the diocotron instability (Plasma Phenomena: Web Ref.) (similar, but different to the Kelvin-Helmholtz instability), that subsequently leads to filamentation. Such vortices can be seen in aurora as “auroral curls” http://www.phys.ucalgary.ca/trondsen/pai/Curls.html. Birkeland currents are also one of a class of plasma phenonena called a z-pinch, so named because the azimuthal magnetic fields produced by the current pinches the current into a filamentary cable. This can also twist, producing a helical pinch that spirals like a twisted or braided rope, and this most closely corresponds to a Birkeland current. Pairs of parallel Birkeland currents can also interact; parallel Birkeland currents moving