External magnetic field effect on plume images and X-ray emission from a nanosecond laser produced plasma

Abstract

The plume images of the laser produced silver plasma in the absence and presence of 0.45 T transverse magnetic field has been investigated under vacuum ~10−4 torr and in air. An Nd:YAG laser (1.064 µm, 1.1 MW, 9 ns) with intensity ~1012 Wcm−2 was used to generate plasma. A CCD image capture system was used for plasma imaging to explore the plume. A magnetic probe was employed to measure the variation in internal magnetic field of plasma with as well as without 0.45 T external transverse magnetic field. The X-ray emission from plasma in both the cases (with and without B field) was also monitored using two PIN photodiodes filtered with 24 µm Cu and 24 µm Al. The plume images in both the cases were then correlated with the time resolved soft X-ray emission. It was found that the self generated magnetic field of the plasma increases in the presence of magnetic field. Plume images reveal that the confinement of the plume takes place in the presence of magnetic field both in the cases of air and vacuum. Jet and spikes like structures were also observed due to plasma instabilities. Lobe formation in the plume at latter stages of plasma evolution was more prominent in air than under vacuum. X-ray emission signals exhibited an enhancement in the emission under transverse magnetic field. An increased rate of recombination due to high density as a result of plasma confinement across the applied magnetic field was found to be the main reason behind emission enhancement.

Ag nanocluster synthesis by laser ablation in Ar atmosphere: A plume dynamics analysis

“…The plasma expansion dynamics was investigated by means of fast photography imaging. Fast photography and plasma spectroscopy have been widely used to gain information about physical quantities that characterize the plasma and to detect the presence of atomic and/or molecular species in the plasma (Thareja & Sharma, 2006;Trusso et al, 2005;Schade et al, 2006;Rafique et al, 2008;Hafeez et al, 2008). In this study, data on physical quantities such as the initial expansion velocity, the mass, the temperature, and the emission intensity as recorded from time resolved fast photography imaging of the expanding plume were used to obtain realistic parameters for the mixed-propagation model.…”

Modifications in surface, structural and mechanical properties of brass using laser induced Ni plasma as an ion source

“…Therefore the expansion of plasma plume and diffusion of plasma species are decelerated by the applied magnetic field. According to Rafique et al 29 the lifetime of plasma plume is increased in the presence of magnetic field. Khaleeq et al 30 reported that the density of laser induced electrons increased in the presence of magnetic field.…”

Effect of external magnetic field on the crystal growth of nano-structured Zn Mn1−+Zr Fe2−2O4 thin films

“…The reason for the improved uniformity and the particle size in case of the film deposited under the influence of external magnetic field is attributed to the enhancement in the forward peaking [17] of Zn, Mn, Zr and Fe ions. The plume is more confined with larger densities under the influence of external magnetic field [13]. In the absence of external magnetic field, the average particle size of the thin film of sample Y, i.e.…”

“…In our previous work, it was reported that there is a change in the plume propagation properties under the influence of an external magnetic field [13], which has significant effect on the growth of thin films [14].…”