Stationary collector in a collisionless plasma

The effect of a neutral collecting body in a collisionless plasma on the plasma distribution in its immediate neighborhood is discussed. When a magnetic field is present an electron plasma with a neutralizing background charge has empty velocity space regions at points near a collector even though the distribution is Maxwellian far from the collector. For a thin cylinder, the collected collisionless plasma current is a function of the angle between the cylinder axis and the magnetic field with the minimum current collected when the cylinder and field lines are parallel