Enhancement and Optimization of Spectroscopic Characterizations of River Soil Plasma Under Magnetic Confinement

This work explores the enhanced spectroscopic characterizations of the soil plasma through the magnetic field-assisted laser-induced breakdown spectroscopy (LIBS) technique and its dependence upon laser fluence. The laser-induced soil plasma has been produced by the employment of Nd:YAG laser (1064 nm) on the surface of the pelletized river soil samples in the absence and presence of a magnetic field of 0.66 T at different laser fluences (30-61 J/cm(2)). Various elements particularly trace elements (arsenic, chromium, manganese, barium, titanium, cobalt, and strontium) were detected in the soil samples, where an enhancement factor of up to 6 times is achieved with the application of a magnetic field to LIBS. The plasma parameters like electron temperature (T-e) and electron number density (n(e)) show an increasing trend with the laser fluence and then decline slightly after 51 J/cm(2) laser fluence but with higher values of these parameters under the magnetic field. The better spectroscopic results are attributed to the magnetic confinement of the plasma, confirmed by the plasma parameter beta(t) < 1. In addition, the threshold laser fluences have been estimated for the soil sample as similar to 6 J/cm(2) and similar to 11 J/cm(2) with and without magnetic field, respectively. The variation in Inverse Bremsstrahlung co-efficient and plasma frequency as a function of laser fluence is also reported. Improved spectroscopic results of magnetic field-assisted LIBS demonstrate it as a promising tool for the detection of multi-elements particularly trace elements in river soil samples.