Geophysical Journal | 2014 volume 36 6

On the impact of MHD resonators on the geomagnetic pulsations

© B.V. Dovbnya, A.S. Potapov, A.V. Guglielmi, R.A. Rakhmatulin, 2014

The examples of the time-frequency structure of geomagnetic pulsations are given. It is shown that in some cases the pulsations of different types may have one thing in common - a discrete structure of the dynamic spectrum. The discreteness is manifested in the alternation of "permitted" and "forbidden" frequencies. Such a structure is analogous to a periodic ripple structure of spectral bands formed by MHD cavities in the magnetosphere-ionosphere plasma. Appearance of discrete spectrum of pulsations is attributed to resonator filtering properties acting on hydromagnetic waves as they pass through the resonant cavity. It is assumed that in some cases the discreteness can provide useful information about the propagation channels of signals of lithospheric or magnetospheric origin.

Key words: resonators, geomagnetic pulsations, discrete structure of spectrum.

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