Noun
an imaginary line paralleling the equator where a magnetic needle has no dip
Source: WordNetFor a simple dipolar solar magnetic field, with opposite hemispherical polarities on either side of the solar magnetic equator, a thin current sheet is formed in the solar wind. Source: Internet
This sets up a sheet of electric current in the E region which, with the horizontal magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from the magnetic equator. Source: Internet