Figure 34. Magnetospheric bow shock as revealed by space-probe measurements. Magnetic field data from orbit 11 of Imp 1. The magnetopause is at 13.6 earth radii. The second transition ' at 20 earth radii to an ordered field outside is the location of the bow shock wave. C. S. Scearce and J. B. Seek, Journal of Geophysical Research 69 (1964). 3531-69; copyright American Geophysical Union, 1964.