Space-resolved measurement of internal magnetic field in a bumpy torus by Li0-beam probe spectroscopy

A new method combining Li0-beam probing and spectroscopic techniques has been developed to measure local magnetic fields in a bumpy torus. A collimated thermal Li0 beam is injected into the plasma. The Zeeman pattern of the lithium resonance radiation (22S-22P, 6708 A) is observed with a Fabry-Perot interferometer. The strength of the local magnetic field is determined from the splitting between two π components of the 22S/sub 1/2/=22P/sub 1/2/ transition with the spatial resolution of about 7 mm. The magnetic fields from 2 to 4 kG were measured with accuracy of +/- 2%. This method is applicable to plasmas of a line-integrated electron density below 5 x 1012 cm-2