LATITUDE DEPENDENCE OF POWER SPECTRA OF MAGNETIC PULSATIONS NEAR L=4 EXCITED BY SCCS AND SIS

Observational evidence from a latitude array of three ground-based magnetometer stations extending from L approximately equals 3. 2 to L approximately equals 4. 4 indicates that the damped-type oscillations excited by storm sudden commencements and sudden impulses contain many spectral peaks. Each spectral peak appears to have a different localization in latitude. The localization in latitude is quite different for the latitudinal and azimuthal (H and D) components. The conjugate magnetic data show that the H components oscillate in phase, while the D components oscillate out of phase at the conjugate pair stations. These observational facts are discussed using a theoretical result concerning the response of the magnetosphere to an impulsive driving force.