Polarization of radiation in turbulent magnetized atmospheres
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Multiple scattering of radiation in a semi-infinite electron atmosphere in the absence of true absorption (the Milne problem) is considered. The electron plasma is assumed to be turbulent, i.e., the magnetic field B has a regular B 0 and a stochastic B′ component (B = B 0 + B′). Faraday rotation of the plane of polarization (s8 λ2 B 0 cos gJ) due to the field B 0 depolarizes the outcoming radiation due to the superposition of rays with different polarization-angle rotations, corresponding to different paths traveled before they left the atmosphere. Stochastic Faraday rotation due to isotropic fluctuations, B′, efficiently decreases the amplitude of the polarization of each individual beam as it travels through the turbulent atmosphere. This effect is proportional to λ4 〈(B′)2〉, and becomes the dominant factor at large λ. We use the Ambartsumian-Chandrasekhar invariance principle, which results in six nonlinear equations (for the field B 0 perpendicular to the surface of the medium). We also compute the degree of polarization for the cases B 0 = 0, B′ ≠ 0, and B′ = 0, B 0 ≠ 0, and for a number of versions of the general case, B 0 ≠ 0, B′ ≠ 0. The spectra of the degree of polarization (for the case B 0 = 0) are presented for optical (λ = 0 − 1 μm), infrared (λ = 1−5 μm), and X-ray (1–50 keV) wavelengths.
PACS numbers95.30.Gv 95.30.Qd 97.10.Ex 97.10.Ld 97.20.Rp 97.60.Jd 97.80.Jp 98.54.Cm
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- 1.O. M. Blaes, in Accretion Discs, Jets and High Energy Phenomena in Astrophysics, Ed. by V. Beskin et al. (Springer, New York, 2003), p. 147.Google Scholar
- 2.A. Z. Dolginov, Yu. N. Gnedin and N. A. Silant’ev, Propagation and Polarization of Radiation in Cosmic Media (Nauka, Moscow, 1979; Gordon and Breach, New York, 1995).Google Scholar
- 8.P. S. Shternin, Yu. N. Gnedin, and N. A. Silant’ev, Astrofozika 46, 433 (2003) [Astrophys. 46, 350 (2003)].Google Scholar
- 9.V. V. Sobolev, Course in Theoretical Astrophysics (Nauka, Moscow, 1968; NASA, Washington, 1969), NASA TT F 531.Google Scholar
- 10.V. A. Ambartsumyan, Astron. Zh. 19, 1 (1942).Google Scholar
- 13.D. A. Varshalovich, V. K. Khersonsky and A. N. Moskalev, Quantum Theory of Angular Momentum (Nauka, Moscow, 1975; World Sci., Singapure, 1988).Google Scholar