PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
OBJECT = TEXT
PUBLICATION_DATE = 1998-09-21
NOTE = "Experiment description for the
Galileo Solar Wind Scintillation Experiments
conducted in 1991-92 (from 91-353 through
92-045), 1993 (from 93-279 through 93-336),
1994 (from 94-309 through 94-361), 1995-96
(from 95-328 through 96-013), and 1996-97
(from 96-361 through 97-044). Formatted for
display or printing with up to 78 constant-
width characters per line."
END_OBJECT = TEXT
END
Although the most interesting region of the solar wind is that
surrounding the Sun, it has not yet been observed directly by spacecraft
measurements. Until missions such as Solar Probe are flown, we must rely on
remote sensing techniques with planetary spacecraft such as Galileo to probe
the inner heliosphere. Radio scintillation and scattering measurements
conducted during the Galileo superior conjunctions represent a powerful and
essentially only tool for studying the complicated solar wind structure near
the Sun.
The Galileo solar wind radio scintillation experiment is based on observations
of radio scattering phenomena that arise from the propagation of radio waves
through the turbulent plasma of the solar wind. These consist of Doppler and
amplitude scintillations (fluctuations), as well as broadening of Galileo's
monochromatic S-band signal (spectral broadening). Characteristics of these
phenomena and the deduced solar wind structure are obtained from the
processing of narrowband DSP recordings of the Galileo radio signal.
Successful DSP recordings are, therefore, important to the scintillation
experiment.
Interplanetary disturbances, which are manifested as transients in the
scintillation and spectral broadening measurements, are of particular interest
in the Galileo experiment. Correlations with events observed on the Sun
(e.g., flares) and at spacecraft located near 1 AU (e.g., Pioneer Venus) will
be made. These correlative studies are clearly most effective if continuous
radio scintillation data are available. For this reason, prolonged periods of
near-continuous tracking of Galileo have been arranged. During the
approximately +1 month period surrounding superior conjunction, the Galileo
radio signal will be probing the solar within about 0.3 AU of the Sun.
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