2-DIMENSIONAL OBSERVATION OF COPPER-VAPOR IN VACUUM ARCS BY LASER-INDUCED FLUORESCENCE

The density distribution and the velocity of copper neutral atoms emit ted from a single cathode spot in 40 A vacuum are were measured by the two-dimensional (2-D) laser-induced fluorescence method, The density was calibrated from the two-dimensional fluorescence image observed by a CCD camera, The gap space was almost filled with the copper atoms, and the density reached 5 x 10(19)/m(3). We varied the wavelength of t he laser light and measured the velocity of the copper atoms emitted f rom the cathode spot using the effect of Doppler shift. The velocity o f the copper atoms was about 10 km/s.