Effect of Coulomb scattering on low-pressure high-density electronegative discharges

• Published in: Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics Vol. 71; no. 2 Pt 2; p. 026403
• Main Authors: Kawamura, E, Birdsall, C K
• Format: Journal Article
• Language: English
• Published: United States 01-02-2005
• Subjects: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANIONS; CATIONS; COMPUTERIZED SIMULATION; COULOMB SCATTERING; FLUX DENSITY; ION DENSITY; KINETIC ENERGY; ONE-DIMENSIONAL CALCULATIONS; P CODES; PLASMA; PLASMA DENSITY; PLASMA HEATING; PLASMA SIMULATION; VELOCITY
• ISSN: 1539-3755; 1063-651X; 1550-2376; 1095-3787
• DOI: 10.1103/PhysRevE.71.026403

For electronegative plasmas with low gas pressure and high ion densities, we expect Coulomb collisions between positive and negative ions to dominate over collisions between ions and neutrals. We incorporated Nanbu's cumulative small-angle collision method [K. Nanbu, Phys. Rev. E, 55, 4642 (1997)] into our one-dimensional three-velocity-component particle-in-cell code PDP1 in order to study the effect of Coulomb collisions on low pressure high density electronegative discharges. Nanbu's method treats a succession of small-angle binary collisions as a single binary collision with a large scattering angle, which is far faster than treating each individual small-angle collision. We find that Coulomb collisions between positive and negative ions in low-pressure high-density electronegative discharges significantly modify the negative ion flux, density, and kinetic energy profiles.