Open AccessRadial mass transport and rotational dynamics
Author(s) -
Pontius Duane H.
Publication year - 1997
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/97ja00289
Subject(s) - physics , angular momentum , magnetosphere , angular velocity , jovian , dipole , radial velocity , astrophysics , mechanics , classical mechanics , plasma , computational physics , stars , quantum mechanics , planet , saturn
The main source of plasma in the Jovian magnetosphere is Io and the dominant sink is outward radial transport. Conservation of angular momentum leads to a decrease in angular velocity with distance, but ionospheric coupling resists any departure from corotation. Competition between these effects predicts a radial dependence for the lag that agrees with observations out to some moderate distance in the middle magnetosphere. However, the observed angular velocity farther out appears to saturate at roughly half the planetary angular frequency, in contrast to the theoretical prediction that it continue to decrease asymptotically to zero. This paper reviews the theory of this phenomenon and explores three of its underlying assumptions as candidates for explaining this discrepancy: (1) Field line stretching from the assumed dipole configuration; (2) a variation in the ratio of the average angular velocity to the average weighted by mass outflux; and (3) a nonlinear response in the atmospheric component of the system.