Mass of Saturn’s magnetodisc: Cassini observations
نویسندگان
چکیده
[1] Saturn’s ring current was observed by Pioneer 11 and the two Voyager spacecraft to extend 8–16 RS in the equatorial plane and appeared to be driven by stress balance with the centrifugal force. We present Cassini observations that show thin current sheets on the dawn flank of Saturn’s magnetosphere, symptomatic of the formation of a magnetodisc. We show that the centrifugal force is the dominant mechanical stress in these current sheets, which reinforces a magnetodisc interpretation – the formation of the current sheet is fundamentally rotational in origin. The stress balance calculation is also used to estimate the mass density in the disc, which show good agreement with independent in-situ measurements of the density. We estimate the total mass in the magnetodisc to be 10 kg. Citation: Arridge, C. S., C. T. Russell, K. K. Khurana, N. Achilleos, N. André, A. M. Rymer, M. K. Dougherty, and A. J. Coates (2007), Mass of Saturn’s magnetodisc: Cassini observations, Geophys. Res. Lett., 34, L09108, doi:10.1029/2006GL028921.
منابع مشابه
A model of force balance in Saturn’s magnetodisc
We present calculations of magnetic potential functions associated with the perturbation of Saturn’s planetary magnetic field by a rotating, equatorially-situated disc of plasma. Such structures are central to the dynamics of the rapidly rotating magnetospheres of Saturn and Jupiter. They are ‘fed’ internally by sources of plasma from moons such as Enceladus (Saturn) and Io (Jupiter). For these...
متن کاملEnceladus plume variability and the neutral gas densities in Saturn’s magnetosphere
[1] Neutral particle dominance over charged particles in Saturn’s magnetosphere was evident prior to Cassini’s arrival at Saturn in 2004. The observation of active plumes emanating from the south pole of Enceladus suggests that this small moon is likely to be the principal source of neutrals in Saturn’s magnetosphere. Cassini has flown through the plumes on several occasions, and the resulting ...
متن کاملIon and neutral sources and sinks within Saturn’s inner magnetosphere: Cassini results
Using ion–electron fluid parameters derived from Cassini Plasma Spectrometer (CAPS) observations within Saturn’s inner magnetosphere as presented in Sittler et al. [2006a. Cassini observations of Saturn’s inner plasmasphere: Saturn orbit insertion results. Planet. Space Sci., 54, 1197–1210], one can estimate the ion total flux tube content, NIONL , for protons, H, and water group ions, W, as a ...
متن کاملSaturn’s Stratospheric Temperature and Composition from Cassini/cirs
We present a short review of our current knowledge on Saturn’s stratospheric thermal structure and composition (hydrocarbons) based on recent Cassini/CIRS observations. Anomalies in the temperature field and in the meridional distribution of hydrocarbons hint at atmospheric dynamical phenomena at play. The two most notable features are an obseved asymmetry in the hydrocarbons distribution at hi...
متن کاملCassini observations of planetary-period magnetic field oscillations in Saturn’s magnetosphere: Doppler shifts and phase motion
[1] Cassini magnetic field observations show that few-nT oscillations near the planetary rotation period, first observed in Pioneer-11 and Voyager-1 and -2 fly-by data, are essentially ubiquitous in Saturn’s magnetosphere, though their character differs between the quasi-dipolar ring current region and the dawn tail. Examination of data from the ringcurrent region shows, however, that the obser...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2007