An Interpretation of the Blue Satellite to Resonance Lines of Helium-like Ions of Third Sequence Elements in Laser-produced Plasmas

It is suggested that the blue satellite to resonance lines of helium-like ions of third sequence elements, observed in laser-produced plasmas by Boiko et at. (1974, 1975) and others and tentatively identified as a Baranger-Mozer satellite, is in fact the blue peak of the self-reversed resonance line profile which has been rendered asymmetrical (red peak enhanced and blue peak suppressed) by differential plasma motion. The various properties reported for the blue satellite are shown to be consistent with model calculations and with the known properties of optically thick, velocity-affected, resonance line profiles of second sequence elements in laser-produced plasmas. The tendency of the satellite to appear preferentially with conical accumulation is explained in terms of the smaller transverse velocities associated with accumulation. One implication of the present interpretation is that, with plane targets, the appearance of an asymmetrically self-reversed line as only a red peak may be the norm rather than the exception; with the further implication that plasma diagnostics based on the misidentification of the red peak as the line proper may be seriously in error.