Experimental evidence for a detached lunar compression wave

Abstract

The behavior of the solar wind flux and direction measured on Explorer 35 in the near lunar wake is presented. The flux near the leading edge of the wake tends to be greater than the free stream value and decreases below detectability near the wake axis. There is probably a small (≲3°) deflection of the wind away from the moon near the leading edge and a deflection toward the wake axis in the region of reduced flux. These features correlate well with variations in the magnetic field. An interpretation of the observed structure is offered that utilizes the theory of two-dimensional steady simple waves in magnetohydrodynamics. A novel feature of the interpretation is the inference of a deflection of the solar wind from the region of the lunar limb to account for the structure near the leading edge of the wake.