Spin modulation periods in Saturn's radio emission as a possible signature of inner dynamo

Patrick H. M. Galopeau 1
1 HEPPI - LATMOS
LATMOS - Laboratoire Atmosphères, Milieux, Observations Spatiales
Abstract : Two distinct and variable rotation periods in Saturn's radio emissions were revealed from observations performed by the radio and plasma wave science (RPWS) experiment on board the Cassini spacecraft. These two periods, at 10.6 hours and 10.8 hours, correspond to SKR produced in the northern and southern hemispheres respectively. The main time modulation of planetary radio emissions has always been attributed to the effect on the inner magnetosphere of the internal magnetic field which rigidly rotates with the deep interior of the planet. As a consequence, the magnetospheric plasma, which is supposed to be frozen in the magnetic field, should rotate (or sub-rotate) with a unique spin period and such a north/south asymmetry in the radio period should never be observed. However, contrary to the other magnetized planets, Saturn presents a very particular magnetic field since its dipolar moment is nearly aligned with the rotation axis of the planet. This alignment could bring out some phenomena developing in the internal structure which are probably masked in the case of the planets the magnetic dipole of which is significantly tilted. We propose to interpret the existence of the two separated and slowly varying periods in the saturnian magnetic field as the signature of the inner dynamo.
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Submitted on : Thursday, June 21, 2012 - 1:58:18 PM
Last modification on : Tuesday, May 14, 2019 - 8:16:02 PM

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Patrick H. M. Galopeau. Spin modulation periods in Saturn's radio emission as a possible signature of inner dynamo. EGU General Assembly 2012, 2012, Vienna, Austria. ⟨hal-00710656⟩

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