Equilibrium properties of inhomogeneous partially-magnetized plasma containing negative ions

This paper presents an analytical model for inhomogeneous, partially-magnetized electronegative plasma. It is shown that the radial potential of the plasma can be related to the electronegativity parameter alpha = n(v)/n(e), the positive ion density, and the electron temperature distribution inside the plasma system. Using this expression, the electronegativity parameter has been determined in an oxygen plasma produced by a 13.56 MHz capacitive coupled radio-frequency discharge, and it is shown that the negative ion parameter obtained using this model is in good qualitative agreement with the saturation current ratio technique based on the cylindrical Langmuir probe.