International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Ganymede
is
composed of rock and ice. It has intrinsic
magnetic field, that makes it an exciting object for investigation.
Its plasma composition is c consists of Jupiter
magnetospheric
particles and ions originated from the surface of
Ganymede. Interaction of Ganymede’s and Jovian magnetospheres
leads to acceleration of ions and complicated transport.
Analysis of ion flux, composition and velocity distribution
provides important tool for Ganymede’s soil composition and
characteristics, not only on local scale but also on planetary scale,
due to transport within Ganymede’s environment.
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
FOOTPRINT OF GANYMEDE
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Auroral
footprint
of
Ganymede
i
s
produced
by
electric
currents
generated
by
motion of
the
satellite
relative Jovian
magnetic field. This current
flow
s
along
Jupiter's
magnetic
field
lines and
exites
the glow
of
the
upper
atmosphere
.
This
ultraviolet
image
of
Jupiter
was
taken
with
the
Hubble
Space
Telescope
Imaging
Spectrograph
(STIS)
on
November
26,
1998
.
T
enuous oxygen
atmosphere of
1.2
×
10
8
–
7
×
10
8
cm
−3
and hydrogen atoms
of ~
1.5
×
10
4
cm
−3
Intrinsic magnetic moment
is about 1.3
×
10
13
T∙m
3
directed against the
Jovian magnetic moment. 720
nT
at equator (Jovian magnetic field 120
nT
).
M
oves
relative to
Jovian
magnetic field with
subsonic velocity. Its
magnetosphere
has diameter
is 4
–
5
R
G
(
R
G
=
2,631.2
km)
Ganymede has
airglow
near
±
50
°
latitude, which is exactly the boundary
between the open and closed field lines of the
Ganymedian
magnetosphere
Relative motion induces magnetic field that suggests
highly conducting
ocean.
Energetic electrons and ions
(tens and hundreds
of
kiloelectronvolts
)
hit
Ganymede’s
surface that leads to
sputtering
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Measurements requirements
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Combination of internal and induced magnetic fields
-
> open magnetosphere
Ganymede’s
surface and atmosphere
Atmospheric/ion composition and its losses to the
magnetosphere
Fluxes of accelerated ions and electrons near
Ganymede
and/or
at its
surface
.
Surface sputtering and implantation of energetic ions
Mapping of surface composition
Jovian magnetosphere and its interaction with
Ganymede
Ion composition of plasma and accelerated particles
Ganymede’s
role in
magnetospheric
plasma population
Magnetospheric
plasma dynamics
Electromagnetic interaction with Jupiter
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Measurements of flux and velocity distribution of
suprathermal
and
energetic
ions,
and mass/charge ion composition for investigation:
-
influence on
Ganymede’s
surface
-
surface composition
-
Ganymede’s
atmospheric losses
-
composition of
Ganymede
and its atmosphere
-
Jovian
magnetospheric
plasma dynamics and the
role of
Ganymede
in Jovian magnetosphere
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
1
2
3
4
8
6
7
9
5
1
–
collimator
,
2
–
electrostatic analyzer
,
3
–
light trap
,
4
–
diaphragm
,
5
–
wedge magnet
,
6
–
drift tube
,
7
–
grids
,
8
–
secondary electron multiplier (SEM)
,
9
–
DC amplifier
,
10
–
pulse counter
Velocity distributions of proton
-
and
α
-
s
measurements in May 1972.
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
1
2
3
4
5
6
Structure of the instrument
:
1
–
angular scanner
,
2
–
electrostatic analyzer
,
3
–
drift tube,
4
–
magnet
,
5
–
focusing electrode
,
6
–
MCP detector
S
imulation results for solar wind ions
Fe
+7
-
Fe
+12
and
O
+5
and O
+6
with E/Q =
1
keV
(1…20
keV
/Q capability)
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
Energy range
,
keV
/Q
1
…20
Mass range
,
M/Q
2…9
Mass resolution,
M/
Δ
m
10
-
40
for
E/Q = 1
keV
Full
angle of view
30
0
х
30
0
for
E/Q = 1
keV
Angular resolution
~2
0
Analyzer
dimensions
,
mm
230х170х120
Estimated mass
,
kg
3.5
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
—
Measurements of ions, electrons and
s
econdary neutral
particles provide important tools for investigation of
Ganymede’s surface characteristics and composition
—
Ion spectrometer under development can
b
e considered as
candidate for plasma suite developed by MSSL and IKI for
exploration of planetary surfaces and planetary
magnetospheres
International Colloquium and Workshop "Ganymede Lander: scientific goals and experiments"
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