Characterization of different light intensity areas for plasma induced during fiber laser-arc hybrid welding

In this paper, fiber laser-arc hybrid welding plasma was studied by using the multiple-imaging method. Four images of plasma with different light intensity areas can be simultaneously observed in a picture. The arc plasma and metal plasma can be distinguished in the high light intensity area, and the arc plasma has an approximate average light intensity distribution. The metal plasma is mainly concentrated above the keyhole, and its temperature/electron density first increases and then decreases along the laser beam direction. The light intensity of plasma is approximately proportional to its temperature in the low light intensity area, and its morphology is similar to its temperature field profile obtained by numerical simulation. By using the multiple-imaging method, the high light intensity area morphology of plasma can be measured, and the simulation results of the plasma temperature field in the low light intensity area can be verified.