Electrojet boundaries and electron injection boundaries.

From observations of the magnetic field along several magnetometer chains motions of the boundaries of auroral electrojets during the active substorm phase have been derived. It turned out that for both electrojets (westward and eastward electrojet) the equatorward boundary is more stable than the poleward one. For both electrojets, however, this boundary correlates quite well with Kp. The Kp dependence of the equatorward electrojet boundary was compared with that of the electron injection boundary after KIVELSON et al. (1980). It turned out that the equatorward boundary of the westward electrojet—but not of the eastward electrojet—coincides quite well with that of the electron injection boundary.