Titan's Induced magnetosphere from plasma wave, magnetic field and
particle observations
Abstract
Cassini plasma wave and charged particle observations are combined with
magnetometer measurements to investigate Titan’s induced magnetosphere.
Electric field emissions close to Titan are identified as upper hybrid
resonance emissions, which provide a density estimate of Titan’s cold
plasma. These observations have been combined with electron spectrometer
measurements to build an integrated map of electron density in Titan’s
near environment using observations from TA to T82 flybys, ie
which includes flybys from the Cassini prime, equinox and part of the
soltice mission. We identify a dense ionospheric region and an extended
plasma wake with values ranging between 10-2 and
103 cm-3. Upstream of the induced
magnetosphere, the presence of pickup ions in the positive hemisphere of
the kronian plasma convective electric field are detected. The mass of
the observed pickup corresponds to methane group ions,
N2+ and HCNH+ ions
as well as Titan’s protons and molecular hydrogen ions. These ions are
progressively accelerated by the kronian background electric field and
we estimate its intensity by reconstructing the energization of this
population. We find values on the order of 0.7 mV/m , consistent with an
average estimate of 0.61 mV/m deduced from ∼ |VxB|
computation.