Effect of magnetic field on the expansion dynamics of laser-blow-off generated plasma plume: Role of atomic processes

摘要

The effect of a variable magnetic field on Li plasma produced by laser-blow-off technique has been studied experimentally. Enhancement in the intensity of the spectral lines from neutrals was observed, which varied with the magnetic field. The enhancement in emission from Li I was found to differ for the two different transitions viz. 670.8 nm (2s S-2(1/2) <- 2p P-2(3/2,1/2)) and 610.3 nm (2p P-2(1/2.3/2) <- 3d P-2(3/2.5/7)), which is more prominent for 670.8 nm. Conventionally, the enhancement in emission in the presence of the magnetic field has been explained in terms of radiative recombination. However, the atomic analysis by computing photon emissivity coefficients in the present case has revealed for the first time that it is due to electron impact excitation.