IAFE   05512
INSTITUTO DE ASTRONOMIA Y FISICA DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Titan's highly dynamic magnetic environment: A systematic survey of Cassini magnetometer observations from flybys TA-T62
Autor/es:
SIMON, SVEN; WENNMACHER, ALEXANDRE; NEUBAUER, FRITZ M.; BERTUCCI, CESAR L.; KRIEGEL, HENDRIK; SAUR, JOACHIM; RUSSELL, CHRISTOPHER T.; DOUGHERTY, MICHELE K.
Revista:
PLANETARY AND SPACE SCIENCE
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Año: 2010 p. 1230 - 1251
ISSN:
0032-0633
Resumen:
We analyze the variability of the ambient magnetic field near Titan
during Cassini encounters TA-T62 (October 2004-October
2009). Cassini magnetometer (MAG) data show that the moon's magnetic
environment is strongly affected by its proximity to Saturn's warped and
highly dynamic magnetodisk. In the nightside sector of Saturn's
magnetosphere, the magnetic field near Titan is controlled by intense
vertical flapping motions of the magnetodisk current sheet, alternately
exposing the moon to radially stretched lobe-type fields and to more
dipolar, but highly distorted current sheet fields. In southern summer,
when most of the Cassini encounters took place, the magnetodisk current
sheet was on average located above Titan's orbital plane. However,
around equinox in August 2009, the distortions of Titan's magnetic
environment due to the rapidly moving current sheet reached a maximum,
thus suggesting that the equilibrium position of the sheet at that time
was significantly closer to the moon's orbital plane. In the dayside
magnetosphere, the formation of the magnetodisk lobes is partially
suppressed due to the proximity of the magnetopause. Therefore, during
most encounters that took place near noon, Titan was embedded in highly
distorted current sheet fields. Within the framework of this study, we
not only provide a systematic classification of all Titan flybys between
October 2004 and October 2009 as lobe-type or current sheet scenarios,
but we also calculate the magnetospheric background field near Titan's
orbit whenever possible. Our results show that so far, there is not a
single Cassini flyby that matches the frequently applied picture of
Titan's plasma interaction from the pre-Cassini era (background field
homogeneous, stationary and perpendicular to the moon's orbital plane).
The time scales upon which the ambient magnetospheric field close to
Titan undergoes significant changes range between only a few minutes and
up to several hours. The implications for the development of numerical
models for Titan's local plasma interaction are discussed as well.