The Mechanisms of Damping of Geomagnetic Pulsationsстатья
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Дата последнего поиска статьи во внешних источниках: 4 августа 2021 г.
Аннотация:The physical mechanisms that might determine the damping rates and resonance widths of Pc3-5 pulsations are considered. To estimate the role of ionospheric dissipation, a numerical model, based on a calculation of the complex eigenfrequencies of Alfven field line oscillations within the approximation of a ''thin'' ionosphere and for a realistic ionosphere has been used. At middle latitudes the Joule dissipation in the ionosphere may account for the experimentally determined width of the resonance peak of the fundamental Alfven mode. The meridional spatial structure of higher harmonics is determined by nondissipative mechanisms. The calculations predict a rapid decrease of the Q factor of the magnetospheric Alfven resonator at L < 1.5. The effect is related to the violation of the thin ionosphere approximation at low latitudes. Experimental support for the calculations was found while analyzing the meridional distribution of the damping rates of P(sc)3 pulsations observed along the 210 degrees magnetic meridian network.