THE MAGNETIC SENSITIVITY OF THE Mg ii k LINE TO THE JOINT ACTION OF HANLE, ZEEMAN, AND MAGNETO-OPTICAL EFFECTS
- Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain)
We highlight the main results of a radiative transfer investigation on the magnetic sensitivity of the solar Mg ii k resonance line at 2795.5 Å, accounting for the joint action of the Hanle and Zeeman effects as well as partial frequency redistribution phenomena. We confirm that at the line center, the linear polarization signals produced by scattering processes are measurable, and that they are sensitive, via the Hanle effect, to magnetic fields with strengths between 5 and 50 G, approximately. We also show that the Zeeman effect produces conspicuous circular polarization signals, especially for longitudinal fields stronger than 50 G, which can be used to estimate the magnetization of the solar chromosphere via the familiar magnetograph formula. The most novel result is that magneto-optical effects produce, in the wings of the line, a decrease of the Q / I scattering polarization pattern and the appearance of U / I signals (i.e., a rotation of the plane of linear polarization). This sensitivity of the Q / I and U / I wing signals to both weak (∼5 G) and stronger magnetic fields expands the scientific interest of the Mg ii k line for probing the chromosphere in quiet and active regions of the Sun.
- OSTI ID:
- 22654162
- Journal Information:
- Astrophysical Journal Letters, Vol. 831, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
Discovery of Scattering Polarization in the Hydrogen Ly α Line of the Solar Disk Radiation
Spatiotemporal Evolution of Hanle and Zeeman Synthetic Polarization in a Chromospheric Spectral Line