Geoscience Reference
In-Depth Information
Fig. 5. Impedance modulus (
left
) measured at 1475 km altitude and 44
◦
invariant lat-
itude by the ISOPROBE quadripole probe (
right
).
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Anti-resonances occur at gyrohar-
monics
nF
c
, while peaks are observed at the plasma frequency
F
p
, the upper-hybrid
frequency
F
t
, and maximum frequencies of the Bernstein's modes
F
qn
.
Fig. 6. Mutual impedance probe accommodation on the CASSINI/HUYGENS probe.
The two transmitting (Tx) and two receiving (Rx) ring electrodes form a trapezoid in a
plane that contains the HUYGENS probe vertical axis. The mutual impedance probe is
one of the permittivity, wave and altimetry, PWA, sensors.
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4. Conclusion
Impedances of short electric field antennae versus frequency are directly
related to plasma characteristics, it therefore allows electron plasma den-
sity and temperature to be reliably and accurately determined. Let us
consider for example a one (or two) meter long antenna whose clos-
est transmitting/receiving electrodes distance is 40 cm (80 cm) driven by
a 2 kHz-2 MHz frequency synthesizer, the plasma density, Debye length,
