## Determination of electron density and electron collision frequency in a nonuniform plasma column by rf coil probe

A nonimmersive-coil-probe method is presented for determining the electron density and electron collision frequency for momentum transfer in a cylindrical plasma column with a Bessel-type density distribution along the radius, the plasma being either isotropic or embedded in an axial static magnetic field. The method is based on the relation between the plasma parameters and the impedance of an rf coil placed coaxially around the plasma. Simplified expressions relating the parameters to the coil impedance are found to be valid under suitable conditions in the isotropic case.