Magnetic Field Studies by Voyager 1: Preliminary Results at Saturn

Abstract

Magnetic field studies by Voyager 1 have confirmed and refined certain general features of the Saturnian magnetosphere and planetary magnetic field established by Pioneer 11 in 1979. The main field of Saturn is well represented by a dipole of moment 0.21 +/- 0.005 gauss-R(s)(3) (where 1 Saturn radius, R(s), is 60,330 kilometers), tilted 0.7 degrees +/- 0.35 degrees from the rotation axis and located within 0.02 R(s) of the center of the planet. The radius of the magnetopause at the subsolar point was observed to be 23 R(s) on the average, rather than 17 R(s). Voyager 1 discovered a magnetic tail of Saturn with a diameter of approximately 80 R(s). This tail extends away from the Sun and is similar to type II comet tails and the terrestrial and Jovian magnetic tails. Data from the very close flyby at Titan (located within the Saturnian magnetosphere) at a local time of 1330, showed an absence of any substantial intrinsic satellite magnetic field. However, the results did indicate a very well developed, induced magnetosphere with a bipolar magnetic tail. The upper limit to any possible internal satellite magnetic moment is 5 x 10(21) gauss-cubic centimeter, equivalent to a 30-nanotesla equatorial surface field.