Sheath characteristics in a magnetically filtered low density low temperature multicomponent plasma with negative ions

摘要: Negative ion rich multicomponent plasma is produced in a novel device for sheath studies. The experimental volume composed of low electron temperature ( T e ∼ 0.2 − 0.4 eV ) and density n 10 5 6 cm 3 argon (Ar) with negative ions. ions are introduced the by injecting sulfur hexafluoride SF gas. Plasma parameters tunable, very close to ionospheric conditions specific D-region. A magnetic filter used, which allows selective diffusion energy electrons from DC discharge source. Positive electron/negative sheaths formed front biased metal plate investigated using an emissive probe. Both positive found be similar thickness symmetric structure. With enhanced concentration, decrease. Poisson's equation derived considering as Maxwellian. results closely follow prediction Debye model. Sheath studies shown here, laboratory plasmas near-ionospheric parameters, important understanding spacecraft-to-plasma interactions design instrumentation.Negative e...