2021/06/02 by Adam Patel, Patel, Adam R., Apoorv Ranjan +9
Engineering · Physics and Astronomy · #Dust and Plasma Wave Phenomena #FOS: Physical sciences #Laser-induced spectroscopy and plasma #Plasma Diagnostics and Applications #Plasma Physics (physics.plasm-ph)
paper · pdf · doi:10.48550/arxiv.2106.02457
openalex publication_date 2021/06/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The total number of electrons in a classical microplasma can be\nnon-intrusively measured through elastic in-phase coherent microwave scattering\n(CMS). Here, we establish a theoretical basis for the CMS diagnostic technique\nwith an emphasis on Thomson and collisional scattering in short, thin\nunmagnetized plasma media. Experimental validation of the diagnostic is\nsubsequently performed via linearly polarized, variable frequency microwave\nscattering off laser induced air-based microplasmas with diverse ionization and\ncollisional features. Namely, conducted studies include a verification of\nshort-dipole-like radiation behavior, plasma volume imaging via intensified\ncharge-coupled device (ICCD) photography, and measurements of relative phases,\ntotal scattering cross sections, and total number of electrons Ne in the\ngenerated plasma filaments following absolute calibration using a dielectric\nscattering sample. Findings of the paper suggest an ideality of the diagnostic\nin the Thomson "free-electron" regime - where a detailed knowledge of plasma\nand collisional properties (which are often difficult to accurately\ncharacterize due to the potential influence of inhomogeneities, local\ntemperatures and densities, present species, and so on) is unnecessary to\nextract Ne from the scattered signal.\n