Fukushima's Theorem
Encyclopedia
In physics
, Fukushima's Theorem holds that for all points beneath the ionosphere the magnetic fields from field-aligned currents and their corresponding Pederson currents exactly cancel. By superposition the total magnetic field at the ground is then equal to the magnetic field from just the ionospheric Hall currents.
Fukushima's Theorem holds in any planar or spherical geometry, provided that the field-aligned currents are perpendicular to the ground, and that the ionospheric conductance is spatially constant. Neither of these conditions holds strongly in the auroral region of the Earth's ionosphere.
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, Fukushima's Theorem holds that for all points beneath the ionosphere the magnetic fields from field-aligned currents and their corresponding Pederson currents exactly cancel. By superposition the total magnetic field at the ground is then equal to the magnetic field from just the ionospheric Hall currents.
Fukushima's Theorem holds in any planar or spherical geometry, provided that the field-aligned currents are perpendicular to the ground, and that the ionospheric conductance is spatially constant. Neither of these conditions holds strongly in the auroral region of the Earth's ionosphere.
Journal articles
- Naoshi FukushimaNaoshi Fukushimawas a Japanese physicist specializing in the near-Earth space environment. He served as Secretary General of the International Association of Geomagnetism and Aeronomy from 1975 to 1983. In 1990 he was awarded the AGU's Waldo E...
, "Equivalence in ground geomagnetic effect of Chapman-Vestine's and Birkeland-Alfven's current systems for polar magnetic storms", Rep. Ionos.Space Res.Jap 23, 219-227 (1969).
- Naoshi FukushimaNaoshi Fukushimawas a Japanese physicist specializing in the near-Earth space environment. He served as Secretary General of the International Association of Geomagnetism and Aeronomy from 1975 to 1983. In 1990 he was awarded the AGU's Waldo E...
, "Generalized theorem for no ground magnetic effect of vertical currents connected with Pedersen currents in the uniform-conductivity ionosphere", Rep. Ionos.Space Res.Jap 30, 35-50 (1976).
- Naoshi FukushimaNaoshi Fukushimawas a Japanese physicist specializing in the near-Earth space environment. He served as Secretary General of the International Association of Geomagnetism and Aeronomy from 1975 to 1983. In 1990 he was awarded the AGU's Waldo E...
, "Some topics and historical episodes in geomagnetism and aeronomy", Journal of Geophysical Research 99, 113–142 (1994).