POMME is a scientific main field model representing the geomagnetic field in the region from the Earth's surface to an altitude of a couple of thousand kilometers. The time variations of the internal field are given by a piece-wise linear representation of the spherical harmonic (Gauss) coefficients of the magnetic potential.
At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.
At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.
At mid- and low-latitudes and during quiet geomagnetic times, electrical currents flowing in the ionosphere generate magnetic variations of a few tens of nT on the ground and at low-Earth orbit altitudes. The Sq ("solar quiet") current system takes the form of two large-scale vortices on the dayside of the Earth, one in each hemisphere. Due to a local enhancement of conductivity, a stronger current, the equatorial electrojet (EEJ), flows along the dip equator and generates magnetic signatures that can reach up to 150 nT at some locations.