Abstract
The behaviour of axially-symmetric waves travelling on plasma filled screened helical coil is comprehensively studied by Anicin [J. Phys. D: Appl. Phys. 33 (2000) 1276], where all analytical expressions are derived in the full-wave theory, but the diagrams are computed in the quasistatic approximation. We use an iterative procedure to overcome this limitation. The iterative procedure is rapid and we have proven that often the first-order approximant is sufficient to improve defects which are known as immanent to the quasistatic approximation. The fixed point method appears as the natural choice for numerical treatment of formulae which could arise in a broad class of physical problems usually recognized as guided surface plasma waves.