Six previously unseen Pan wakes are found interior and exterior to the
Encke gap in Saturn's A ring, one in the Voyager 2 photopolarimeter (
PPS) stellar occultation data and five in the Voyager 1 radio science
(RSS) earth occultation data. Pan orbits at the center of the Encke ga
p and maintains it. Originally it was hypothesized that a wake would b
e completely damped by the time it reached a longitude of 360 degrees
relative to Pan. However, five of the six newly detected wakes are at
longitudes in excess of 360 degrees and are a result of earlier encoun
ters with Pan. The sixth is the first detection of the RSS outer Pan w
ake, The new PPS inner wake is at a longitude of 389.8 degrees. The ne
w RSS inner wakes are at longitudes of 519.4 degrees +/- 1.6 degrees a
nd 879.4 degrees +/- 1.6 degrees. The RSS outer wakes are at longitude
s of 200.6 degrees +/- 1.6 degrees, 560.6 degrees +/- 1.6 degrees, and
920.6 degrees +/- 1.6 degrees. Because of the time needed for a wake
to develop after encountering Pan, the higher order wakes (longitude >
360 degrees) can be more prominent than their lower order counterparts
which are superimposed at the same location. The radial dispersion be
havior of the Pan wakes are characterized using a Burg autoregressive
power spectral algorithm. The wake radial wavelength behavior is compa
red to a simple model which ignores collisions and self-gravity, The f
our wakes with longitudes below 360 degrees show an average deviation
of 0-3% from the predicted wavelengths, indicative of the strength of
collective effects. The detection of Pan wakes at longitudes greater t
han 360 degrees demonstrates that wakes persist for much longer than o
riginally hypothesized and may interact with one another, The presence
and characteristics of these wakes will provide an important test of
kinetic theory models. (C) 1996 Academic Press, Inc.