INVESTIGADORES
BERTUCCI Cesar
congresos y reuniones científicas
Título:
The Structure of Titan's Ionosphere from 10 Years of Cassini Measurements: Solar Cycle and Saturn Local Time Dependence
Autor/es:
EDBERG, N. J. T.; KURTH, W. S.; GURNETT, D. A.; ANDREWS, D. J.; VIGREN, E.; SHEBANITS, O.; AGREN, K.; WAHLUND, J. E.; OPGENOORTH, H. J.; HOLMBERG, M.; JACKMAN, C. M.; CRAVENS, T.; BERTUCCI, C.; DOUGHERTY, M. K.
Reunión:
Congreso; AGU Fall Meeting 2014; 2014
Resumen:
We present measurements from the Cassini Radio and Plasma Wave
Science/Langmuir probe (RPWS/LP) instrument of the electron density in
the ionosphere of Titan from the first ~100 flybys (2004-2014). After
more than 10 years of measurements a good number of measurements exists
from Titan's ionosphere. This allows for statistical studies of the
structure of Titan's ionosphere. The electron density has been shown to
vary significantly from one flyby to the next, as well as on longer time
scales and here we discern some of the reasons for the observed
ionospheric variability. Firstly, following the rise to the recent solar
maximum we show how the ionospheric peak density, normalized to a common
solar zenith angle, Nnorm clearly varies with the ~11-year solar cycle.
Nnorm correlates well with the solar energy flux Fe and we find that
Nnorm ∝ Fek, with k = 0.54 ± 0.18, which is close to the
theoretical value of 0.5. Secondly, we present results that indicate
that the ionospheric density in the topside ionosphere (altitude range
1200-2400 km) are generally significantly increased, roughly by a factor
of 2, when Titan is located in the post-midnight sector of Saturn, i.e.
at Saturn local times 00 - 03 h, compared to other local time sectors.
We suggest that this increase could be caused by additional particle
impact ionization from reconnection events in the Saturn tail.