Ion collection by oblique surfaces of an object in a transversely flowing strongly magnetized plasma.

The equations governing a collisionless obliquely flowing plasma around an ion-absorbing object in a strong magnetic field are shown to have an exact analytic solution even for an arbitrary (two-dimensional) object shape, when temperature is uniform, and diffusive transport can be ignored. The solution has an extremely simple geometric embodiment. It shows that the ion collection flux density to a convex body's surface depends only upon the orientation of the surface and provides the theoretical justification and calibration of oblique "Mach probes." The exponential form of this exact solution helps explain the approximate fit of this function to previous numerical solutions.