Influence of axial magnetic field on angular distribution of charge and energy of laser produced slow and fast tungsten ion groups. (March 2023)

• Record Type: Journal Article
• Authors: Abbasi, Shahab Ahmed; Dogar, Ashiq Hussain; Rafique, Muhammad; Dawood, Asadullah; Qayyum, Hamza; Qayyum, Abdul
• Is Part Of: Vacuum. Volume 209(2023)
• Publication Date: 2023-03
• Subjects: Angular distribution -- Ions -- Laser ablation -- Magnetic field -- Tungsten -- Bimodal structure; Vacuum -- Periodicals; 621.55
• DOI: 10.1016/j.vacuum.2022.111781
• Languages: English
• ISSNs: 0042-207X

Abstract

Abstract: Here effect of magnetic field on the angular distribution of laser produced tungsten (W) ions is reported. Plasma plume was generated by irradiating surface of W target, placed inside a vacuum chamber under magnetic field of 0.23 T, by nanosecond pulsed laser beam. Angular distribution of W ion flux was measured with the help of an ion collector (IC) and explained under the framework of Anisimov model. Magnetic field clearly split the ion signals temporally into comparable fast and slow ion components and enhanced the intensity of fast ion group significantly. Enhancement of ion charge state with B was confirmed by Ion energy analyser (IEA). Theoretical fitting of bimodal ion signal suggested the existence of thermal and non-thermal component of nanosecond laser produced plasma. With magnetic field, a two fold increase in total charge of the fast ion component was observed. Magnetic field effect on ion energy was also investigated. The optical emission spectrum of W plasma was also recorded, and plasma parameters were measured in both the absence and presence of magnetic field. The rise of electron temperature and number density in presence of B confirmed the heating of W plasma by magnetic field. Highlights: Angular distribution of laser produced slow and fast tungsten ion groups in presence of magnetic field is investigated. Magnetic field clearly split the tungsten ion signals temporally into comparable fast and slow ion components. In presence of magnetic field the intensity of fast ion group is enhanced significantly. Existence of thermal and non-thermal component in nanosecond laser produced plasma is verified. 100% enhancement in emitted charge of fast ion group and 15% enhancement in the total emitted tungsten ion charge is recorded.