Session GP1 - Poster Session IV.
POSTER session, Tuesday afternoon, October 30
Exhibit Hall B,
A laser induced fluorescence (LIF) diagnostic is being developed for use with plasmas generated by a planar spheromak gun. LIF line broadening corresponding to T_i=19.9 eV Doppler broadening has been demonstrated in a prior experiment in an argon plasma generated by a coaxial spheromak gun. Light from an Nd:YAG pumped, tunable dye laser is directed through an optical fiber to probe the plasma. The laser pulse width is 15 ns, and the argon discharge duration is 20-30 \mus. Synchronization between the pulsed laser (15 Hz repetition rate) and the single-shot plasma device is achieved with CAMAC time delay modules. The fluorescent signal light is measured by a fast photomultiplier after passing through a narrow bandwidth (10 Åfilter centered on the emission wavelength. A critical requirement in any LIF experiment is reproducibility of the plasma. We present images from a gated, intensified CCD camera demonstrating that we have achieved good reproducibility in argon plasmas produced by the planar gun configuration. We expect to present preliminary LIF measurements from these plasmas.