Transcript of A. Milillo, and the GENIE Team. Golden Age of of Solar System Exploration Ganymede’s and...
- Slide 1
- A. Milillo, and the GENIE Team
- Slide 2
- Golden Age of of Solar System Exploration Ganymedes and Europas
Neutral Imaging Experiment (GENIE) GENIE is a
high-angular-resolution detector of Energetic Neutral Particles
(energy range 10s eV few keV) (ENP) based on the ToF technique,
optimized to flown in the Jupiters environment. Its objective is to
map the origin sites of the ENP of the icy moons exospheres, in
order to investigate the interaction between the surface and the
environment. Rome, 10-12 Sep. 2012
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- Ion impact onto an icy surface Golden Age of of Solar System
Exploration Intense ion fluxes impacting onto the icy moons
surfaces produce neutral particle release that originates the
exospheres. The observations at proper angular resolution of the
higher- energy neutrals produced by the plasma-surface interaction
will provide an instantaneous 2D imaging. Rome, 10-12 Sep.
2012
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- Golden Age of of Solar System Exploration Comparative
observations Similar energetic ion fluxes are expected at Europa
and Ganymede, composed by a similar iced surface but with the
difference of an internal magnetic field that could shield the
plasma or define preferential entries and plasma precipitation
regions On the contrary, the ion fluxes at Callisto are
considerably lower. Similar observations in different environment
like the three moons would offer the chance to investigate the
satellites evolution in the Jupiter system.
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- Europa vs Ganymede Golden Age of of Solar System Exploration
Europa is the simplest case since it has not an internal magnetic
field. The plasma precipitation is just due to the interaction with
the obstacle. The release variations at low spatial scale are
mainly driven by different surface properties. Ganymede with its
internal magnetic field has a complex interaction with the Jupiters
magnetospheric plasma. Rome, 10-12 Sep. 2012
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- Surface released velocity spectra @ Europa (Plainaki et al.,
2011, Icarus). Major components of released particles are H 2 O
(produced by direct ion sputtering), O 2 and H 2 (produced by
radiolysis and sputtering). H (via ion back scattering) could be
relevant at velocities above 100 km/s. Golden Age of of Solar
System Exploration Escape velocity: 2 km/s Rome, 10-12 Sep.
2012
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- Neutral particles release @ Europa Golden Age of of Solar
System Exploration (Plainaki et al., Icarus, 2012). The ENP
differential flux above 10 eV from the surface can be estimated
about 510 8 p.cle/(cm 2 s sr eV) at Europa O 2 released by H +, O +
and S + impact and radiolysis H 2 O released by H +, O + and S +
sputtering. Note that IS is a stochiometric process, so it releases
all the species trapped into the surface. Rome, 10-12 Sep. 2012
Leading Trailing Leading Detection of ENP at high spatial
resolution from the surface will permit to investigate the global
asymmetries and to relate the local surface release efficiency to
surface features and purity of ice. This will be an important piece
of the evolution puzzle.
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- Ganymedes surface Rome, 10-12 Sep. 2012Golden Age of of Solar
System Exploration Ganymede is the unique discovered moon in the
Solar system with a dipolar magnetic field. Very close
correspondence has been demonstrated between the observed
higher-albedo polar cap boundary and open/closed field lines
boundary (Khurana et al., 2007).
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- Ganymedes magnetosphere Rome, 10-12 Sep. 2012Golden Age of of
Solar System Exploration The Jupiters plasma overcomes the moon
from the trailing side. At Ganymede, as in the Mercurys case, the
fluxes precipitate in the open-field lines areas. (Massetti
courtesy, 2011) 1 keV10 keV100 keV (Jia et al. 2008)
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- ENP release @ Ganymede Golden Age of of Solar System
Exploration 1-keV O + simulations by Massetti in the MHD magnetic
field model by Jia et al., 2008 The magnetic field permits the
exosphere generation only in specific regions. Leading O + FLUX (cm
-2 s -1 keV -1 ) LeadingTrailing Jupiter Rome, 10-12 Sep. 2012
Detection of ENP at high spatial resolution from the surface will
permit to dynamically map the precipitating regions (auroral
mapping) and to relate them to surface features (like different
albedo). This is a kind of second vantage point observation for
precipitating plasma. This will be an outstanding new way to
investigate the coupling between the Jupiters plasma and the
Ganymedes magnetic field. H2O released by O+ sputtering simulation
by Mura
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- Primary and synergic GENIE science goals Golden Age of of Solar
System Exploration For each Galiean moon: Ganymede, Europa and
Callisto, GENIE is aimed: To characterize in space and in energy
the radiating component of the exospheres; To study the
interactions of the moons with the Jovian magnetosphere; To
discriminate and depict the exospheres generation mechanisms.
Moreover, the possibility to operate GENIE at the three moons
permits To compare the different environments. For each Galiean
moon: Ganymede, Europa and Callisto, GENIE is aimed: To
characterize in space and in energy the radiating component of the
exospheres; To study the interactions of the moons with the Jovian
magnetosphere; To discriminate and depict the exospheres generation
mechanisms. Moreover, the possibility to operate GENIE at the three
moons permits To compare the different environments. Rome, 10-12
Sep. 2012 Synergic science goals with other JUICE payload
experiments are: To characterize the complete exospheric energy
distribution with INMS and UV spectrometer; To characterize the
surface release process with Particle Package and magnetometer; To
investigate weathering and erosion of surface features; with
Surface multi-wavelength spectroscopy; To determine how much the
Ganymede escape influence the Jupiters aurorae with Particle
Package, magnetometer and UV imaging. Synergic science goals with
other JUICE payload experiments are: To characterize the complete
exospheric energy distribution with INMS and UV spectrometer; To
characterize the surface release process with Particle Package and
magnetometer; To investigate weathering and erosion of surface
features; with Surface multi-wavelength spectroscopy; To determine
how much the Ganymede escape influence the Jupiters aurorae with
Particle Package, magnetometer and UV imaging.
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- Golden Age of of Solar System Exploration GENIE pointing To see
the surface emission, the sensor must point toward the moon surface
(nadir). For instance, in order to resolve surface features of the
order of 30 km, an angular resolution of about 5 degrees is
required from an altitude of 350 km above the moon surface. Rome,
10-12 Sep. 2012
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- Golden Age of of Solar System Exploration Entrance 5x60 with
ion deflector. START section: Shutter System (BC/SERENA-ELENA
heritage) ToF chamber STOP section: signal detection system
Anticoincidence section: background detection system. GENIE basic
concept Rome, 10-12 Sep. 2012
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- High-angular resolution low-energy neutral atom detection by
means of micro-shuttering techniques Heritage at IAPS Golden Age of
of Solar System Exploration SERENA/ELENA will be delivered to ESA
in mid 2013
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- BepiColombo-MPO/SERENA-ELENA Golden Age of of Solar System
Exploration The basic sections of ELENA sensor are: a charge
particle deflector for ions suppression; an entrance with a grating
system which may work as: a shuttering system, based of coupled
moving slits of nanometric dimension, which permits the neutrals to
enter in the sensor only when the slits are aligned, defining the
detection START time. UV suppressor; a ToF chamber; a STOP system
based on the technique of MCP technologies. Rome, 10-12 Sep.
2012
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- Example: ELENA shutter at 10 kHz Golden Age of of Solar System
Exploration At MEFISTO facility in Bern University, the
functionality of the ELENA shutter has been tested to verify the
open/closed timing. 1-keV-H beam through the shuttering system
detected by the MCP. Rome, 10-12 Sep. 2012
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- Conclusions Golden Age of of Solar System Exploration Without
ENP observations there is no way to univocally relate the exosphere
to surface features and to monitor instantaneously the effect of
plasma precipitation onto the surface. ENP investigation is the
link between magnetospheric science and surface science. ENP
detection could be a support for interpreting other instrument
observations. This kind of measurement is new, especially for icy
surfaces where sputtering is the dominant process; hence, any
observation will produce a big science return. ENP observations are
feasible, even if the noise issue must be carefully addressed,
especially during the Europa flybys. GENIE has no strong
constraints (distances or pointing requirements) for the
spacecraft. The required GENIE resources are not demanding for the
spacecraft. Rome, 10-12 Sep. 2012