Abstract

POBLET, Facundo Leandro  and  AZPILICUETA, Francisco. Variación de ~27 días en la actividad magnética terrestre: características globales y un nuevo enfoque basado en el origen de las señales27-day variation in terrestrial magnetic activity: global characteristics and a new approach based on the origin of the signals. Geoacta [online]. 2016, vol.41, n.2, pp.17-31. ISSN 1852-7744.

The terrestrial magnetic field has a wide range of temporal variations. In a first instance they can be classified according to whether they come from the magnetic field of internal origin as the secular variation or crustal induced currents, or if they come from external sources. In the latter case, the main responsible is the Sun that causes from regular variations such as the diurnal variation to some more irregular ones for example those that produce magnetic storms. The physical process that triggers them it is not the same in all cases. In this paper, the variation of approximately 27 days of periodicity in the H component of the terrestrial magnetic field, associated to solar rotation is investigated. The most recurrent feature of this signal, obtained after various processing steps in an intend to isolate it, is the presence of other periodicities coupled to its amplitude: a strong amplitude modulation by the solar cycle and a second semiannual modulation. Finally, a comparative analysis with other ~27 days signals in the solar parameters F10.7 and Mg II index, and ionospheric vTEC allows to establish that the physical process that gives rise to the signal in the magnetic activity is associated with the solar wind and not to its electromagnetic radiation.

Keywords : Solar wind; Solar radiation; 27-day variation; Cross-correlation.

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