HR: 1330h
AN: SM22B-0239    [PDF]
TI: Do the Jovian Bow Shock and Magnetopause Surfaces in the Joy et al. (2002) Model Predict Measured Boundary Normals Correctly?
AU: * Joy, S P
EM: sjoy@igpp.ucla.edu
AF: UCLA Institute of Geophysics and Space Physics, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: * Joy, S P
EM: sjoy@igpp.ucla.edu
AF: UCLA Dept. of Earth and Space Science, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: Kurth, W S
EM: william-kurth@uiowa.edu
AF: University of Iowa, Dept. of Physics and Astronomy, Iowa City, IA 52242-1479 United States
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: UCLA Institute of Geophysics and Space Physics, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: Kivelson, M G
EM: mkivelson@igpp.ucla.edu
AF: UCLA Dept. of Earth and Space Science, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: Walker, R J
EM: rwalker@igpp.ucla.edu
AF: UCLA Institute of Geophysics and Space Physics, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AU: Walker, R J
EM: rwalker@igpp.ucla.edu
AF: UCLA Dept. of Earth and Space Science, 405 Hilgard Ave, Los Angeles, CA 90095-1567 United States
AB: Joy et al. (2002) provided probabilistic descriptions of the jovian bow shock and magnetopause by mapping spacecraft observations to the sub-solar point along model surfaces derived from the MHD simulation of Ogino et al. (1998). The resulting statistics are strongly affected by the surface models used in the mapping process. Here we analyze the quality of the surface models used in that mapping by comparing the normal directions of the observed boundary crossings to the normal directions predicted by the surface models. We have identified 116 magnetopause and 74 bow shock crossings in the Galileo data from orbits 0 through 34 using both the plasma wave (PWS) and magnetometer (MAG) data sets. We have determined the boundary normal directions for both these newly identified crossings and the previously published crossings of Galileo, Ulysses, Voyagers 1 and 2, and Pioneers 10 and 11. When possible, boundary normals were determined from the MAG data by using the minimum variance technique of Sonnerup and Cahill. Some boundary crossings could not be analyzed because of data gaps or inadequate sampling resolution. The boundary crossings are well distributed in local time ($\sim$03:00 to 19:00) and are mostly near equatorial. Initial results indicate that the shape models used by Joy et al. (2002) are reasonable. We will examine the small non-zero mean difference between the observed and model boundary normal directions to determine whether the discrepancy is statistically significant. The large variance of the normal direction about the mean may imply that the normal directions fluctuate because of surface waves on the boundaries or that steady-state surface models do not apply in the presence of changing solar wind conditions.
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2728 Magnetosheath
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
DE: 5737 Magnetospheres (2756)
DE: 6220 Jupiter
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting