Dynamics of Dayside Aurora in Relation to Solar Wind - Magnetosphere Interaction

摘要

Photometric observations of dayside auroras are related to simultaneous measurements of geomagnetic disturbances from meridian chains of observatories on the dayside and on the nightside, to document the dynamics of dayside auroras in relation to local and global disturbances. These observations are related to measurements of the interplanetary magnetic field (IMF) and the solar wind velocity from the satellites ISEE 1 and ISEE3. Information on field-aligned currents from spacecraft MAGSAT is also discussed. It is shown that the dayside part of the auroral oval expands equatorward (contracts poleward) in concert with increase (decrease) of the field-aligned current magnitude and with the growth (decay) of circumoval/polar cap geomagnetic disturbance. A model is proposed to explain the equatorward and poleward movements of the dayside oval in terms of a dayside current system with the generator potential linearly related to the southward component of the IMF vector. (Atomindex citation 16:034092)