Effect of magnetic field on laser induced breakdown spectroscopy of zirconium dioxide (ZrO2) plasma

Laser induced breakdown spectroscopy of ZrO2 plasma in the presence and absence of magnetic field has been investigated. The plasma was generated by employing Nd: YAG laser (1064 nm, 10 ns) at various fluences ranging from 6.4 J cm−2 to 25.6 J cm−2 under argon environment of pressure of 100 Torr. Both emission intensity and electron temperature show increasing trend with increasing the fluence, whereas, electron number density of ZrO2 plasma decreases with increasing the laser fluence. It is revealed that values of emission intensity, electron temperature and electron number density of ZrO2 plasma are slightly higher in the presence of magnetic field as compared to field free case at all fluences. This increase in plasma parameters is attributed to magnetic confinement and Joule heating effect. With the variation of fluence the electron temperature of ZrO2 plasma varies slightly from 5345 K to 5475 K in the absence of magnetic field, whereas in case of magnetic field this value enhances from 5435 K to 5600 K. Similarly the electron number density of ZrO2 plasma varies from 1.80 × 1018 cm−3 to 3.50 × 1018 cm−3 in the absence of magnetic field, whereas in case of magnetic field, the variation in electron number density varies from 1.75 × 1018 cm−3 to 4.25 × 1018 cm−3. The existence of magnetic confinement effects is confirmed by the analytical evaluation of plasma parameter β, which is smaller than 1 under all experimental conditions. It is also revealed that both the laser fluence as well as magnetic field significantly influence the ZrO2 plasma parameters.