Determination of magnetic field direction in a comet's head

Abstract The Stokes parameters of resonance radiation scattered by a Na atom with the angular momentum F aligned by directed unpolarized radiation in a magnetic field H ∼ 10 −5 −10 −1 Oe are presented. An influence of the orientation of the magnetic field on these parameters are studied; the intensity ratio I(D 2 ) I(D 1 ) changes within ±5%, and the polarization degree P ( D 2 ) within ±25%. Measurements of I(D 2 ) I(D 1 ) and P ( D 2 ), if the geometry of scattering is known, may give information on the direction of the magnetic field in the sodium atmospheres of comets, as well as Io's sodium cloud or man-made cosmic clouds.