An investigation of the linear polarization in emission features of active regions

• Published in: Solar physics Vol. 103; no. 1; pp. 11 - 20
• Main Author: FIRSTOVA, N. M
• Format: Journal Article
• Language: English
• Published: Boston, MA Reidel 1986; Dordrecht
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Other topics on the solar system; Solar system; Solar spectrum; Rectilinear polarization; Hα line; Hβ line; Active region
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/BF00154854

A study has been made of the linear polarization in moustaches by using the H alpha and H beta lines. A Wollaston prism and an achromatic lambda /2-plate were used in the study. In the course of the observations, the major axis of the plate was placed at 0 and 22.5 degrees with regard to the horizontal axis of the installation. The Stokes parameters (J, Q, and U) were recorded, making possible the determination of the degree of polarization and the field azimuth. During the first 3 min of the existence of the moustaches, the two lines revealed a linear polarization of similar to 7% located at the center of the lines. No polarization was found during the later stage of the moustaches' lifetimes. Whenever the linear polarization is present, there is a tendency for the polarization to decrease rapidly when accompanied by a turning of the azimuth. Several mechanisms for interpreting the polarization observed in the moustaches are examined. Suggestions are made in support of the excitation of hydrogen atoms in the moustaches initiated by a high-energy electron flux or vertical heat conduction.