| | |
Summary: Adv. Space Res. Vol. 1, pp.
69--73. 0273--1177/81/0301--0069$05.OO/O
© COSPAR, 1981. Printed in Great Britain.
UPPER ATMOSPHERE OF
JUPITER--A POST VOYAGER
PERSPECTIVE
S. K. Atreya
Department of Atmospheric and Ocean Science,
Space Physics Research Laboratory, The University of
Michigan, Ann Arbor, Michigan 48109, USA
From the time of Pioneer observations in 1973--74 to the Voyager encounters in
1979, the Jovian upper atmospheric temperature has increased by about 30% to a
value of ll00±200K~the eddy diffusion coefficient at the homopause decreased by a
factor of about lO~to a value of -106 cm2 s~, the equatorial disc Lyman alpha
intensity increased by a factor of 30, to 14 kIt, and the equatorial ionosphere
became more extensive and showed diurnal variation. Many of these changes are
believed to have resulted from a change in solar activity and the mechanisms re-
sponsible for upper atmospheric heating. The upward propagating inertia gravity
waves are expected to supply a constant source of heat,not varying with the solar
activity. The penetration of the magnetospheric soft electrons, Joule heating
|
