Damping standing Alfven waves in the magnetosphere

Using the WKB approximation, we analyze the phase and energy structure of d amped Alfven wave structures in a magnetospheric field configuration. In th e WKB limit the real part of the eigenfrequency is determined by the field line length while the damping rate is determined by the ionospheric conduct ivity. Expressions are worked linking the damping decrement to the ionosphe ric damping, and it is shown that the damping effect of each ionosphere add s linearly to the damping decrement. We end with a critique of the use of t he WKB solution for Alfvenic wave structures and indicate where such soluti ons may be unreliable.