An effect of the ionospheric Alfvén resonator on multiband Pc1 pulsations

Autor: K. Prikner, K. Mursula, J. Kangas, R. Kerttula, F. Z. Feygin
Jazyk: angličtina
Rok vydání: 2004
Předmět:
Zdroj: Annales Geophysicae, Vol 22, Pp 643-651 (2004)
Druh dokumentu: article
ISSN: 0992-7689
1432-0576
DOI: 10.5194/angeo-22-643-2004
Popis: On 2 December 1999, the magnetometer stations in northern Finland registered structured Pc1 activity simultaneously in three distinct frequency bands. Using simultaneous EISCAT radar measurements of the high-latitude ionosphere, we have studied the ionospheric resonator properties during this multiband Pc1 event. The frequencies of the three structured Pc1 bands were found to closely correspond to the second, third and fourth harmonic of the calculated fundamental frequency of the ionospheric Alfvén resonator (IAR). In addition, those frequencies of the three pearl bands that were closest to the exact IAR harmonics were found to have the strongest intensities. The results demonstrate that the resonator can have an important role on ground-based Pc1 activity over a notably large frequency range, favoring transmission of waves with frequencies close to the resonator's eigenfrequencies. Since the frequencies of all three bands correspond to the maximum rather than the minimum of the transmission coefficient, the traditional bouncing wave packet model needs to be revised. Key words. Ionosphere (auroral ionosphere; ionosphere magnetosphere interactions; wave propagation)
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