The interaction of a flowing plasma with Titan was studied. A Monte carlo simulation method is planned for the determination of the average flow field and pressure/temperature variations about Titan. Jupiter's magnetic field was also studied. Polynomial expressions describing this magnetic field are discussed briefly

Jones, D. E.

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PROGRESS REPORT
-AmS GRANT NAG 2-145
"Pioneer 10 and 11 (Jupiter and Saturn) ffegnetometer Experiments"
covering the period April 1, 1984 - Sept. 30, 1984
Brigham Young University
Provo, Utah, 84602
Principal Investigator: Douglas E. Jones
Sept. 5, 1984<-
The NASA Technical Officer .for this grant is R. 0. Fimmel
NASA-AMES Research Center
Moffett Field, CA 94035
https://ntrs.nasa.gov/search.jsp?R=19840027170 2020-03-20T21:46:41+00:00Z
During this reporting period we have continued our studies of the
interaction of a flowing plasma with Titan. This effort was suggested as a
result of a study of the work conducted to date by other researchers in which
it was concluded that the conditions at Titan were sufficiently different from
those at Venus,- in a plasma domain in which little is known, or assumptions to
date regarding the flow of the plasma around the "obstacle" could give very
inaccurate results. We have decided to use a Monte-Carlo simulation to
determine the average flow field and pressure/temperature variations about
Titan. The results are quite encouraging, but only the simplest of
interaction configurations has been utilized to date. In future work we hope
to include more realistic conditions,!,e., the effects of the magnetic field,
mass loading, ionization, and charge exchange, etc. This work will be the
subject of a PhD dissertation by the primary graduate student on this project,
Gordon Wilson.
In a joint study with Barry Thomas (JPL/CTT) and Michael Regler (CTT), we
have continued to pursue our efforts in terms of the low latitude cusp that
resulted from models of the dayside Jovian magnetosphere. In this particular
study, the best fit image dipole, tail and ring current configurations were
kept fixed, and a polynomial expression for the remaining magnetic field was
computer minimized. This polynomial expression was of second order in
rectangular coordinates (SM) in which divergence free and symmetry conditions
were imposed. The minimum residuals were similar to those obtained using a
simple dawn-dusk sheet current, and field lines derived from the polynomial
expression appeared to have characteristics that were definitely "sheet-
like." However, it was clear that some characteristics of the field lines due
to this type of "current" produced fields distinctly different from that of
the sheet, i.e., a localized oval shaped enhancement in the field (weaker both
nearer and further from the planet). A second order version of the model gave
a smaller residual than obtained with the sheet and we have been tempted to
interpret the field enhancement near the magnetopause, that is due to the
polynomial expression, in terms of additional currents that need to be
included. Although providing a cusp that is higher in latitude than that
reported previously (although similar to that obtained with return current
sheets above and below the equatorial sheet), it is still significantly lower
in latitude than expected based upon terrestrial type models. Our future
studies of the problem of the low latitude cusp will continue to utilize a
polynomial type field, but we will have started a joint study with Ray Walker
of UCLA in which "D" shaped currents to represent both the magnetopause and
dawn-dusk currents will be utilized. Such an effort was undertaken some time
ago for the earth by Pfitzer and Olson, and in fact it is precisely their
computer algorithm that we will adapt to Jupiter in a function minimization '
mode.


Pioneer 10 and 11 (Jupiter and Saturn) magnetometer experiment

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