The electrostatic shielding of a charged absorbing object (dust grain) in a
flowing collisionless plasma is investigated by using the linearized kinetic
equation for plasma ions with a point-sink term accounting for ion absorption
on the object. The effect of absorption on the attractive part of the grain
potential is investigated. For subthermal ion flows, the attractive part of the
grain potential in the direction perpendicular to the ion flow can be
significantly reduced or completely destroyed, depending on the absorption
rate. For superthermal ion flows, however, the effect of absorption on the
grain attraction in the direction perpendicular to the ion flow is shown to be
exponentially weak. It is thus argued that, in the limit of superthermal ion
flow, the effect of absorption on the grain shielding potential can be safely
ignored for typical grain sizes relevant to complex plasmas.Comment: 25 pages, 3 figure