Flow velocities in the P.S.-3.5 spheromak

The authors have investigated flow fields in the P.S.-3.5 spheromak by observing shifts of spectral lines from carbon impurity ions in the plasma and assuming the shifts are due to the Doppler effect. By passing the plasma light through a spectrometer and imaging it on the detector head of an optical multichannel analyzer (OMA), both spectral and spatial resolution are obtained during a short time interval (2.0 μsec). By comparing the spectral data from the plasma with know lines from a standard lamp, absolute line shifts of +..02A can be determined. The optical system accepts the light emitted side-on (i.e., along a line perpendicular to the plane containing the spheromak symmetry axis) so as to enable toroidal and radial flows to be detected on the midplane of the spheromak. The results reported here are based on observations of the 2297A line of C III