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The effect of magnetic field on the plasma parameters and surface modification of Cu-alloy has been investigated. For this purpose, we have employed Nd: YAG laser at various irradiances ranging from 1.9 to 5 GW/cm2 to irradiate Cu-alloy under 5 torr pressure of argon, neon, and helium. The evaluated values of excitation temperature (Texc) and electron number density (ne) of Cu-alloy plasma explored by laser-induced breakdown spectroscopy technique are higher in the presence of 1.1 Tesla magnetic field as compared with field-free case. It is true at all irradiances as well as under all environmental conditions. It is also found that trends of both Texc and ne are increasing with increasing laser irradiance from 1.9 to 4.4 GW/cm2. For the highest used irradiance 5 GW/cm2, the decrease in both parameters is observed. The analytically calculated values of thermal beta, directional beta, confinement radius, and diffusion time for laser-irradiated Cu-alloy plasma confirm the validity of magnetic confinement. Scanning electron microscope analysis is utilized to study the surface modifications of laser-irradiated Cu samples and reveals the formation of islands, craters, cones, and droplets. The finer-scale surface structures are grown in case of magnetic. It is also revealed Texc and ne play a substantial part in the growth of surface structures on Cu-alloy.

The effect of the transverse magnetic field on laser-induced breakdown spectroscopy and surface modifications of germanium (Ge) has been investigated at various fluences. Ge targets were exposed to Nd: YAG laser pulses (1064 nm, 10 ns, 1 Hz) at different fluences ranging from 3 to 25.6 J/cm2 to generate Ge plasma under argon environment at a pressure of 50 Torr. The magnetic field of strength 0.45 Tesla perpendicular to the direction of plasma expansion was employed by using two permanent magnets. The emission spectra of laser-induced Ge plasma was detected by the laser-induced breakdown spectroscopy system. The electron temperature and number density of Ge plasma are evaluated by using the Boltzmann plot and stark broadening methods, respectively. The variations in emission intensity, electron temperature (Te), and number density (ne) of Germanium plasma are explored at various fluences, with and without employment of the magnetic field. It is observed that the magnetic field is responsible for significant enhancement of both excitation temperature and number density at all fluences. It is revealed that an excitation temperature increases from Te,max,without B = 16,190 to Te,max,with B = 20,123 K. Similarly, the two times enhancement in the electron density is observed from ne,max,without B = 2 × 1018 to ne,max,with B = 4 × 1018 cm−3. The overall enhancement in Ge plasma parameters in the presence of the magnetic field is attributed to the Joule heating effect and adiabatic compression. With increasing fluence both plasma parameters increase and achieve their maxima at a fluence of 12.8 J/cm2 and then decrease. In order to correlate the plasma parameters with surface modification, scanning electron microscope analysis of irradiated Ge was performed. Droplets and cones are formed for both cases. However, the growth of ridges and distinctness of features is more pronounced in case of the absence of the magnetic field; whereas surface structures become more diffusive in the presence of the magnetic field.