Diapositive 1

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CENTRE NATIONAL DE LA RECHERCHE
SCIENTIFIQUE Laboratoire de Physique et Chimie de
l'Environnement et de lEspace 3A, avenue de la
Recherche Scientifique F-45071 Orléans cedex 02,
France
Mutual Impedance MEasurements, MIME as part of
the EJSM JGO/RPWI Jean Gabriel TROTIGNON and
Jean Louis Rauch LPC2E, CNRS, Université
dOrléans, Orléans, France
EJSM JGO/RPWI Team Meeting, 26-27 Nov. 2009
Phone [phone] Fax [phone]
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
r
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EJSM JGO/RPWI Team Meeting, 26-27 Nov.
2009 Mutual Impedance MEasurements, MIME as part
of the EJSM JGO/RPWI
Presentation Outline
Experiment Objectives Principle of
Measurements Range of Measurements
Heritage Instrument Conclusion
Téléphone (33 2) 38 25 52 63 Secrétariat (33
2) 38 25 52 64 Télécopie (Fax) (33 2) 38 63 12
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
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JGO/RPWI/MIME Experiment Objectives (1 / 2)

• Provide reliable/accurate measurements of total
  plasma density thermal electron temperature, in
  Jupiter system environment (solar wind included)
• Contribute to the study of the interactions
  between solar wind Jupiters Magnetosphere, in
  particular around Ganymède and Callisto
• Give insight into thermal coupling between
  neutral charged particles
• Detect plasma boundaries and identify plasma
  regimes

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JGO/RPWI/MIME Experiment Objectives (2 / 2)

• Enable self and/or mutual impedances of LP-PWI
  and possibly RA-PWI electric antennae to be
  determined as a function of plasma environment
• Determine the effective length of these
  antennae (then allow E-field component of waves
  to be calibrated)
• Possibly measure the physical/deployed length
  of antennae
• Contribute to onboard calibrations of LP-PWI,
  and maybe SCM and RA-PWI (calibration signal can
  be delivered)
• ? cross-calibration between sensors.

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MIME Principle of Measurements
A sinusoidal signal of known amplitude
frequency, coming from a current (or voltage)
generator, is applied to antenna probe or wire
shield, by short pulses (some ms), while induced
voltage (or current) is simultaneously
measured. Antenna impedance Z V / I is a
function of frequency plasma conditions. Transm
itted frequency varies step by step in a
frequency bandwidth that includes the plasma
frequency expected at Jupiters Magnetosphere (Ne
proportional to Fpe2). Impedance spectra are
computed onboard by FFT/DFT algorithms. Plasma
parameters, such as density and electron
temperature, are derived from variations of both
impedance modulus and phase close to Fpe.
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MIME Principle of Measurements (contd)

• Thermal electron temperature Te shall be
  determined provided
• 2 ?D lt L lt a few tens ?D ,
• where L is the tip-to-tip antenna length
  and the plasma ?D Debye Length
• For the total electron density Ne, L must be
  higher than ?D and can be higher
• than a few tens ?D depending on the onboard
  FFT frequency resolution
• Ne can be determined from resonance and/or wave
  signatures at the plasma frequency Fpe, the
  upper-hybrid frequency Fuh and Berstein mode
  frequencies Fqn
• As a bonus, the magnetic field strength B can be
  derived from the electron cyclotron frequency Fce
  and its gyroharmonics nFce
• Ne (cm-3) Fpe2 (kHz) / 81
• Fce (Hz) 28 B (nT)
• Fuh (Fpe Fce)1/2
• Fpe (kHz) 6687 Te1/2 (eV) / ?D (cm)

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4 March 2005, 221239.14 UT, 0 dB 0.6 µV Hz1/2
2,090 km altitude
Fpe 468 kHz 1.17 Fce ? Ne 2,700 cm-3
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CENTRE NATIONAL DE LA RECHERCHE
SCIENTIFIQUE Laboratoire de Physique et Chimie de
l'Environnement et de lEspace 3A, avenue de la
Recherche Scientifique F-45071 Orléans cedex 02,
France
MIME Range of Measurements
Phone [phone] Fax [phone]
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
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Fpe (kHz) Ne cm-3 10-3 eV ?D (cm) 0.01 eV ?D (cm) 0.1 eV ?D (cm) 1 eV ?D (cm) 10 eV ?D (cm) 100 eV ?D (cm)
0.285 0.001 740 2.35 103 7.4 103 2.35 104 7.42 104 2.35 105
0.705 0.006 300 949 3 103 9.5 103 3 104 9.5 104
1 0.012 210 670 2.1 103 6.7 103 2.1 104 6.7 104
2.1 0.05 100 320 103 3.2 103 104 3.2 104
2.23 0.06 300 950 3 103 9.5 103 3 104
6.7 0.55 100 316 103 3.2 103 104
7 0.6 300 955 3 103 9.6 103
10 1.23 21 67 210 670 2.1 103 6.7 103
21 5.4 100 318 103 3.2 103
22 6 300 960 3 103
67 55 100 316 103
70 60 300 955
100 123.5 2.1 6.7 21 67 210 670
210 540 100 318
220 300
670 5.5 103 100
1 000 1.2 105 0.2 0.67 2.1 6.7 21 67
3 500 1.5 105 0.06 0.2 0.6 2 6 19
9 000 106 0.02 0.07 0.23 0.74 2.35 7.4
Comparison between a 2 x 3 m long antenna (green)
and a 2 x 1 m one (yellow) Ne and Te should be
measured provided 0.5 cm ?D 3 m (or 1
m)
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Callisto (Gurnett et al., 2000) Ne 400 cm-3
(180 kHz) at 535 km gt 100 cm-3 (90 kHz) at 500 -
600 km Iomospheric peak 7 000 17 000
cm-3 (750 1200 kHz)
at 30-50 km
Ganymede (Gurnett et al., 1996
Eviatar et al., 2001) Ne 200 300 cm-3 (130
160 kHz) at 1 000 km Ne peak 400 - 2 500
cm-3 (180 450 kHz)
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• ? Expected MIME Range of Measurements
• Frequency bandwidth from a few hundred Hz up
  to 3 MHz
• Debye length from 0.5 cm up to 1-3 m
  (depending on antenna length)
• Total plasma density 0.01 1.5 105 cm-3
• Electron temperature 0.01 100 eV.
• The E-field antenna is assumed to be of the order
  of 2 to 6 m tip-to-tip long
• (the longer, the better)

Lower-frequency signals can be produced for
sensor calibrations (TBD)
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CENTRE NATIONAL DE LA RECHERCHE
SCIENTIFIQUE Laboratoire de Physique et Chimie de
l'Environnement et de lEspace 3A, avenue de la
Recherche Scientifique F-45071 Orléans cedex 02,
France
Mutual Impedance Technique Heritage The
mutual/self impedance measurement technique has
successfully been used, during nearly three
decades, onboard ionospheric rockets and
spacecraft (GEOS, VIKING, MARS 96, ROSETTA, and
more recently BepiColombo/MMO).
Phone [phone] Fax [phone]
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
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Mutual Impedance Technique Heritage (contd)
Active Impedance Modulus
Passive Natural waves
Active Impedance Phase
ROSETTA/RPC/MIP Observations in the Earths
Plasmasphere
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Mutual Impedance Technique Heritage (contd)
Numerical Simulations for BepiColombo/MMO Both
the capacitance and the resistance of the MEFISTO
antenna exhibit a peak at the plasma frequency
(gt density) and a plateau below (gt
temperature). Here, Debye length is 5 m, which
is a typical value in solar wind close to Mercury
(30 m antenna tip-to-tip length).
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CENTRE NATIONAL DE LA RECHERCHE
SCIENTIFIQUE Laboratoire de Physique et Chimie de
l'Environnement et de lEspace 3A, avenue de la
Recherche Scientifique F-45071 Orléans cedex 02,
France
MIME Instrument
Phone [phone] Fax [phone]
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
r
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Global view of MIME instrument
(?) also to SCM for calibrations (TBD)
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Possible Electrical Interface here AM²P-E to
MEFISTO on BepiColombo/MMO
Output signals of synthesizer are referenced to
ground
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Electrical Interfaces MIME to E-Field Antenna(e)
Detail of possible interface with E-Field
antenna(e) for wire and mutual modes
synthesizer
MIME output switch
Safety relay
MIME
Sensor Electronics
E-Field Sensor
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RPWI/MIME Elements

• MIME may be composed of the following elements
• The electronic board hosted in RA (it would
  allow MIME to be connected to every
  electric/magnetic sensors)
• Current probes hosted by E-field antenna
  deployment boxes (as in BepiColombo/MEFISTO
  ones)
• EGSE including data processing software.

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MIME possible working modes
I " measured by MIME current probe V " measured
by LP/PWI
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MIME Measurement Point Definition

• A MIME measurement point contains 3 pieces of
  information
• Reference spectrum (no transmission)
• Power spectrum
• Phase spectrum
• from which Ne, Te, antenna impedances are
  derived on ground.

Note to increase SNR, each frequency may be
transmitted n times depending on MIME working
modes, and averages will therefore be computed
onboard.
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MIME power and mass ressources
(BepiColombo/MMO/AM2P)
Mass 13 g each Power consumption 50 mW Size 52
mm x 52 mm
(Rosetta/MIP)
Mass 470 g (1.3 g / cm2) Power consumption 1.3
W (1.6 W peak) Size 247 mm x 147 mm
(BepiColombo/AM2P)
Mass 240 g (0.8 g / cm2) Power consumption 0.5
W (0.7 W peak) Size A5
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MIME Telemetry Ressources
Survey 1952 bits / 60 s (33 bits s-1) Ref.
spectrum (passive) 64 frequency bins x 10 bits x
1 Power spectrum 64 frequency bins x 10 bits x
1 Phase spectrum 64 frequency bins x 10 bits x
1 HK 32 bits Nominal 6976 bits / 30 s (233
bits s-1) Ref. spectrum 96 frequency bins x 12
bits x 2 Power spectrum 96 frequency bins x 12
bits x 2 Phase spectrum 96 frequency bins x 12
bits x 2 HK 64 bits Burst 12 352 bits / 10 s
(1 235 bits s-1) Ref. spectrum 128 frequency
bins x 16 bits x 2 Power spectrum 128 frequency
bins x 16 bits x 2 Phase spectrum 128 frequency
bins x 16 bits x 2 HK 64 bits
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E-Field Antenna Occupancy
Example N 24 (frequency step repetition
factor for a high signal to noise
ratio) Frequency sweep 128 different frequency
steps (FFT 256 samples) 3 Frequency bands 200
Hz 20 kHz 2 kHz 200 kHz 20 kHz 2 MHz 1 or
2 acquisition channels Acquisition time (worst
case) 855 ms (including time for the plasma to
be stabilized)
1 MIME channel
Ref
F0
F1
F126
F127
OR
Frequency repeated N times
2 MIME channels
F1
Ref
F0
F126
F127
F1
Ref
F0
F126
F127
MIME emission 2 times shorter
Frequency repeated N/2 times
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CENTRE NATIONAL DE LA RECHERCHE
SCIENTIFIQUE Laboratoire de Physique et Chimie de
l'Environnement et de lEspace 3A, avenue de la
Recherche Scientifique F-45071 Orléans cedex 02,
France
Mutual Impedance MEasurements, MIME as part of
the EJSM JGO/RPWI J. G. Trotignon and J. L.
Rauch
Conclusion Thank you, first, for the invitation
to participate in this exciting mission MIME
may definitely contribute to the study of the
Jupiter magnetosphere, in particular in
measuring the electron plasma density and
temperature, determining the effective length of
electric antennae, helping out with in-flight
sensor calibrations. Application for funding has
been submitted to CNES.
Phone [phone] Fax [phone]
34 E-mail Jean-Gabriel.Trotignon_at_cnrs-orleans.f
r