Solar Polarization

Novel instruments for high-precision imaging polarimetry have opened new possibilities, including for exploring effects in radiative scattering, atomic physics, spectral line formation, and radiative transfer. This volume gives a comprehensive and up-to-date account of this rapidly evolving and interdisciplinary field of science.

Much progress has been made in recent years in understanding the complex physics of polarized radiation in the sun and stars. This physics includes vector radiative transfer and spectral line formation in the presence of magnetic fields, scattering theory and coherence effects, partial redistribution and turbulent magnetic fields, numerical techniques and Stokes inversion, as well as concepts for polarimetric imaging with a precision limited only by photon statistics. The present volume gives a comprehensive and up-to-date account of this rapidly evolving field of science.

Novel instruments for high-precision imaging polarimetry have opened new possibilities, including for exploring effects in radiative scattering, atomic physics, spectral line formation, and radiative transfer. This volume gives a comprehensive and up-to-date account of this rapidly evolving and interdisciplinary field of science.

The physics of microwave-burst emission is briefly examined to give the rationale for investigating polarization spectra. The instruments used to carry out the 9.4 GHz and 7 GHz circular-polarization measurements and the 5 GHz Stokes-parameter measurements are described. A survey of the August 1972 to December 1973 period produced a table of 45 bursts, from which some limited results were obtained. About 75 to 80 percent of all bursts are circularly polarized, with varying polarization over the 5 to 9.4 GHz range. For most bursts where the circular polarization pc increases toward the upper or lower end of the 5 to 9.4 GHz range, the total intensity I also increases in that direction. The few bursts having a pc sense reversal in the 5 to 9.4 GHz range also have a spectral maximum of I at roughly the same frequency. Some simplified explanations of the results are presented.

This book covers advances made since the 2004 Springer volume “Polarized Light in Animal Vision” edited by Horvath and Varju, but also provides reviews and synopses of some areas. Part I examines polarization sensitivity across many animal taxa including vertebrates and invertebrates and details both terrestrial and aquatic life. Part II is devoted to the description of polarized light in nature and explores how the physics of light must be taken into account when understanding how polarized light is detected by the visual system. This includes underwater polarization due to scattering; polarization patterns reflected from freshwater bodies; polarization characteristics of forest canopies; normal and anomalous polarization patterns of the skies; skylight polarization transmitted through Snell’s window and both linearly and circularly polarized signals produced by terrestrial and aquatic animals. This Part also examines polarized “light pollution” induced by anthropogenic factors such as reflection off asphalt surfaces, glass panes, car bodies, and other man-made structures that are now known to form ecological traps for polarotactic insects. Part III surveys some of the practical applications of polarization vision including polarization-based traps for biting insects, ground-based polarimetric cloud detectors and an historical examination of the navigational abilities of Viking seafarers using the sky polarization compass. The deterrent qualities of ungulate pelage to polarization-sensitive biting insects is also examined in this section.

Polarization Spectroscopy of Ionized Gases describes the physical principles of the technique and its applications to remote sensing. Transport phenomena and local anisotropies can be studied. The theoretical part of the book considers the basic phenomena of the ordering of the velocities of fast exciting charged particles. The polarization of the outer electron shells of excited atoms or molecules is described, and a variety of effects are examined in detail. An integral equation is derived which gives the intensity and polarization of emitted lines. Methods for solving the equation are analyzed. Universal spectropolarimetric remote sensing has been applied to low pressure gas discharges in the laboratory and to non-thermal processes in the solar atmosphere. For researchers interested in the remote sensing of ionized gases.

This book elaborates on the physical principles of polarization remote sensing. It explains the reflective characteristics of surface objects and atmosphere separately, including theory, experiment, instrument and application. In addition, it introduces how polarization remote sensing works in advanced research programs as it can be used in aviation, astronomy, disaster risk prevention and navigation fields. This book serves as a fundamental and comprehensive reference for researchers and students.

This book discusses analytic and asymptotic methods relevant to radiative transfer in dilute media, such as stellar and planetary atmospheres. Several methods, providing exact expressions for the radiation field in a semi-infinite atmosphere, are described in detail and applied to unpolarized and polarized continuous spectra and spectral lines. Among these methods, the Wiener–Hopf method, introduced in 1931 for a stellar atmospheric problem, is used today in fields such as solid mechanics, diffraction theory, or mathematical finance. Asymptotic analyses are carried out on unpolarized and polarized radiative transfer equations and on a discrete time random walk. Applicable when photons undergo a large number of scatterings, they provide criteria to distinguish between large-scale diffusive and non-diffusive behaviors, typical scales of variation of the radiation field, such as the thermalization length, and specific descriptions for regions close and far from boundaries. Its well organized synthetic view of exact and asymptotic methods of radiative transfer makes this book a valuable resource for both graduate students and professional scientists in astrophysics and beyond.