One Fluid MHD 2D Simulations
Measurements from Lunar Prospector ( Lin et. al., Science, vol. 281, 4 Sept. 1998, pg 1480-1484)
suggested that when the strong magnetic anomalies in the vacinity of the
Serentatis and Imbrium impact antipodes faced into the solar wind, shock-like
structures, or mini-magnetospheres, could form. These are part of the results
from the initial simulations to test their theory.
The simulation used a 2 step Lax-Wendroff to solve the MHD equations in a
300x200 grid. Two nested boxes were used for increased resultion, with the
plots a portion of the highest resolution grid. The tick marks equal 8.7km
and the solar wind is incident from the left hand side. The top of the plot
is near the equitorial region of the Moon. The anomaly was created with a
buried dipole.
Picture Key : All the figures follow this convention, but are zoomed into the region of interest. The "x"s indicate the location of the dipole.
(From Harnett and Winglee, JGR, vol. 105, Nov. 2000).
Pressure Contours for three different magnetic field configurations. In Figure (a) the IMF only has components in the ecliptic plane. In Figures (b) and (c) the IMF is in the Southward directions, but the dipole moment in Figure (c) has been flipped by 180 degrees.
(From Harnett and Winglee, JGR, vol. 105, Nov. 2000).
Case B : Density, magnetic field lines and velocity vectors when the dipole moment is parallel to the IMF, thus the surface field is anti-parallel to the IMF and pointing northward.
(From Harnett and Winglee, JGR, vol. 105, Nov. 2000).
Case C : Density, magnetic field lines and velocity vectors when the dipole moment is anti_parallel to the IMF, thus the surface field is parallel to the IMF and pointing soutward.
(From Harnett and Winglee, JGR, vol. 105, Nov. 2000).
Two Dipoles : Density, magnetic field lines and velocity vectors for
two dipoles with their moments parallel to the IMF.
Simulated Satellite Data for Case C The spots on Figures (a) and (b) indicate the positions at which the data in Figures (c) and (d) was sampled, and arrows indicate the positions at which the density (a) and the magnetic field (b) reach their maximal values. The simulated data agrees with the result from Lunar Prospector, indicating that the maximum density was seen before the maximum magnetic field magnitude.
(From Harnett and Winglee, JGR, vol. 105, Nov. 2000).
eharnett at ess.washington.edu
Last modified: Tue Jun 22 14:25:44 PDT 2004
