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The parameters of a plasma produced by irradiation of alkali hydride targets with a ruby‐laser pulse are experimentally measured. Positive‐ and negative‐ion abundances are determined with a quadrupole mass analyzer. Electron temperature was measured with rapidly swept Langmuir probes. Negative (H−) ion temperature was obtained using the mass analyzer and focusing grids. The electron density near the target was determined by optical holography. The quantity of negative ions produced per laser pulse make the source attractive for the future development of high‐energy neutral‐beam systems.

Beams of negative ions have been extracted from a plasma generated in a laser‐initiated arc passing through a vapor released from an alkali hydride. Beam duration has been greater than 15 msec. An attainable H− production efficiency of 41 kW/A is indicated by the present experiment. Such a source would have certain key advantages over other proposed negative ion sources.