Periodic motion of the magnetodisk as a cause of quasi-periodic variations in the Kronian magnetosphere. (1st October 2016)

• Record Type: Journal Article
• Authors: Nemeth, Z.; Szego, K.; Foldy, L.; Cowley, S.W.H.; Provan, G.; Thomsen, M.
• Is Part Of: Planetary and space science. Volume 130(2016)
• Page Start: 54
• Page End: 59
• Publication Date: 2016-10-01
• Subjects: Saturn -- Magnetosphere -- Periodic variations -- Magnetodisk; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2016.07.002
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: Most of the phenomena that describe the magnetized plasma filling the huge magnetosphere of Saturn exhibit periodic behavior. The fundamental period reflected in many magnetospheric phenomena is the rotational period of the planet, but the relationship is not at all trivial. In most cases clear periodic behavior can be found only for relatively short time intervals, and often even in these intervals abrupt phase-shifts occur and non-rotational frequencies appear. Several sophisticated methods have been developed to filter out interfering fluctuations and find the basic periodicity and phase of the variations. Although these methods proved to be very useful, some information is inevitably lost in the process. To recover this otherwise lost information we follow a different strategy to analyse the quasi-periodic variations of the plasma properties. We assume that the motion of the magnetodisk is periodic and that the observed quasi-periodic variations are due to the interplay of this periodic motion and the effects governing the spatial dependence of the plasma parameters ( F ), especially their dependence on the distance ( d ) from the central sheet of the magnetodisk. We found that relatively simple F ( d ) functions are able to reproduce the observed complex temporal dependence of the plasma properties. Highlights: Quasi-periodic signals around Saturn explained by a single underlying periodicity. Very good analytic fits for the radial magnetic field, density and azimuthal speed. Plasma properties can be calculated from each other, which provides even better fits. Quasi-periodic variations probably driven by the periodic motion of the magnetodisk.