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Cassini's successful orbit insertion has provided the first examination of Saturn's magnetosphere in 23 years, revealing a dynamic plasma and magnetic environment on short and long time scales. There has been no noticeable change in the internal magnetic field, either in its strength or its near-alignment with the rotation axis. However, the external magnetic field is different compared with past spacecraft observations. The current sheet within the magnetosphere is thinner and more extended, and we observed small diamagnetic cavities and ion cyclotron waves of types that were not reported before.

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The magnetic field signature obtained by Cassini during its first close encounter with Titan on 26 October 2004 is presented and explained in terms of an advanced model. Titan was inside the saturnian magnetosphere. A magnetic field minimum before closest approach marked Cassini's entry into the magnetic ionopause layer. Cassini then left the northern and entered the southern magnetic tail lobe. The magnetic field before and after the encounter was approximately constant for approximately 20 Titan radii, but the field orientation changed exactly at the location of Titan's orbit. No evidence of an internal magnetic field at Titan was detected.

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[1] The first close Titan encounters TA, TB, and T3 of the Cassini mission at almost the same Saturnian local time $1030 and in the same spatial region downstream of Titan have enabled us to study the formation of the tail of its induced magnetosphere. The study is based on magnetic field and electron plasma observations as well as threedimensional modeling. Our most important findings are the following: (1) No crossings of a bow shock of Titan were observed, and all encounters occurred at high plasma b > 1 for transsonic and trans-Alfvénic Mach numbers. (2) The magnetic draping signature of the induced magnetosphere often shows a sharp outer boundary called the draping boundary (DB) in the near-tail region. (3) The DB is often occurring as a discontinuity in magnetic field spatial derivatives, and therefore the DB is a discontinuity in the spatial distribution of plasma currents. (4) Perpendicular to the incident flow direction the DB shows an approximately elliptic cross section elongated along the incident magnetic field direction and a displacement toward the Sun. (5) We argue that the DB in the magnetic tail region corresponds to the boundary of a structure which is analogous to an Alfvén wing at very small b and in our case of larger b contains Alfvénic and slow mode features. It forms a tail like a delta wing in aerodynamics. (6) For the two less disturbed flybys, TA and T3, a polarity reversal layer has been observed with thicknesses of $320 km and $230 km, respectively.

After 3 years and 31 close flybys of Titan by the Cassini Orbiter, Titan was finally observed in the shocked solar wind, outside of Saturn's magnetosphere. These observations revealed that Titan's flow-induced magnetosphere was populated by "fossil" fields originating from Saturn, to which the satellite was exposed before its excursion through the magnetopause. In addition, strong magnetic shear observed at the edge of Titan's induced magnetosphere suggests that reconnection may have been involved in the replacement of the fossil fields by the interplanetary magnetic field.