Abstract
The diffuse reflection of line radiation from a one dimensional semi-infinite turbulent atmosphere is examined in two limiting regimes of micro-and macroturbulence. Ambartsumyan’s invariance principle is used to solve this problem. In addition to the observed spectral line profile, statistical averages describing the diffusion process in the atmosphere (mean number of scattering events, average time spent by a photon in the medium) are determined. The dependence of these quantities on the average hydrodynamic velocity and scattering coefficient is studied. It is shown that in the microturbulent regime the intensity at the line center depends only slightly on the mean nonthermal velocity. In both regimes, photons in the far wings undergo scattering more frequently than in a static atmosphere, although they spend, on average, less time in the medium.
Similar content being viewed by others
References
A. G. Nikoghossian, Astrofizika 50, 219 (2007).
C. Magnan, J. Quant. Spectrosc. Radiat. Transfer 15, 979 (1975).
H. Frisch, Astron. Astrophys. 40, 267 (1975).
H. Frisch and U. Frisch, Mon. Notic. Roy. Astron. Soc. 175, 157 (1976).
C. Magnan, J. Quant. Spectrosc. Radiat. Transfer 16, 281 (1976).
H. P. Gail, E. Hundt, W. H. Kegel, J. Schmid-Burgk, and G. Traving, Astron. Astrophys. 32, 65 (1974).
H. P. Gail and G. Traving, Astron. Astrophys. 44, 421 (1975).
G. Batchelor, The Theory of Homogeneous Turbulence, Cambridge Univ. Press, 6th ed.
E. S. Venttsel’, Probability Theory [in Russian], Nauka, Moscow (1964).
N.B. Yengibarian and A.G. Nikoghossian, Astrofizika 8, 71 (1972).
A.G. Nikoghossian and H.A. Haruthyunian, in: The Invariance Principle and its Applications [in Russian], Izd. AN ArmSSR, Erevan (1980), pp. 232–241.
H.A. Haruthyunian and A.G. Nikoghossian, J. Quant. Spectrosc. Radiat. Transfer 19, 135 (1978).
D. Hummer, Mon. Notic. Roy. Astron. Soc. 125, 21 (1962).
D. Mihalas, Stellar Atmospheres, Freeman & Co., San Francisco (1970).
E. Tandberg-Hanssen, The Nature of Solar Prominences, Kluwer, Dordrecht (1995).
H.A. Haruthyunian and A.G. Nikoghossian, DAN SSSR 242, 66 (1978).
A.G. Nikoghossian, Astrofizika 21, 323 (1984).
A.G. Nikoghossian, Astrofizika 24, 149 (1986).
Author information
Authors and Affiliations
Additional information
__________
Translated from Astrofizika, Vol. 50, No. 3, pp. 391–403 (August 2007).
Rights and permissions
About this article
Cite this article
Nikoghossian, A.G. Diffuse reflection of line radiation from a semi-infinite turbulent atmosphere. Astrophysics 50, 321–332 (2007). https://doi.org/10.1007/s10511-007-0031-9
Received:
Issue Date:
DOI: https://doi.org/10.1007/s10511-007-0031-9