Circular polarization induced by scintillation in a magnetized medium

A theory is presented for the development of circular polarization as radio waves propagate through the turbulent, birefringent interstellar medium. T he fourth order moments of the wave field are calculated, and it is shown t hat unpolarized incident radiation develops a nonzero variance in circular polarization. A magnetized turbulent medium causes the Stokes parameters to scintillate in a nonidentical manner. A specific model for this effect is developed for the case of density fluctuations ina uniform magnetic field.