Related papers: Observing the Second Solar Spectrum at IRSOL
This paper shows the first synthetic tomography of the quiet solar chromosphere formed by spatial maps of scattering polarization. It has been calculated for the CaII 8498, 8542 and 3934 A lines by solving the NLTE (non-local…
Scattering polarization signals offer a unique diagnostics of the physical conditions in the solar atmosphere, in particular magnetic fields via the Hanle effect. However, their spatial structure remains poorly constrained due to the…
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 angstrom, accounting for the joint action of the Hanle and Zeeman effects as well as partial…
One of the key research problems in stellar physics is to decipher the small-scale magnetic activity of the quiet solar atmosphere. Recent magneto-convection simulations that account for small-scale dynamo action have provided…
The solar photosphere is filled by a magnetic field which is tangled on scales much smaller than the resolution capability of solar telescopes. This hidden magnetic field can be investigated via the Hanle effect. In 2007 we started a…
The Hanle effect in strong spectral lines is the physical mechanism that should be increasingly exploited for quantitative explorations of the magnetism of the quiet solar chromospheric plasma. Here we show, by means of multilevel radiative…
High sensitivity observations of Halpha polarization of 30 flares of different sizes and disk positions are reported. Both filter and spectrographic techniques have been used. The ZIMPOL system eliminates spurious polarizations due to…
A particularly interesting line for exploring the physical conditions of the quiet solar chromosphere is H$\alpha$, but its intensity profile is magnetically insensitive and the small circular polarization signatures produced by the…
The weak, turbulent magnetic fields that supposedly permeate most of the solar photosphere are difficult to observe, because the Zeeman effect is virtually blind to them. The Hanle effect, acting on the scattering polarization in suitable…
The polarization of radiation by scattering on an atom embedded in combined external quadrupole electric and uniform magnetic fields is studied theoretically. Limiting cases of scattering under Zeeman effect and Hanle effect in weak…
An attractive diagnostic tool for investigating the magnetism of the solar chromosphere is the observation and theoretical modeling of the Hanle and Zeeman effects in spicules, as shown in this letter for the first time. Here we report on…
Here we report on the first observational investigation of the Zeeman effect in the G band around 4305 A. Our spectropolarimetric observations of sunspots with the Zurich Imaging Polarimeter at the IRSOL facility confirm our previous…
We report the first measurement of the zodiacal light (ZL) polarization spectrum in the near-infrared between 0.8 and 1.8 $\mu$m. Using the low-resolution spectrometer (LRS) on board the Cosmic Infrared Background Experiment (CIBER),…
Stellar prominences detected in rapidly rotating stars serve as probes of the magnetism in the corona of cool stars. We have synthesized the temporal evolution of the Stokes profiles generated in the He I 10830 and 5876 A triplets during…
Scattering polarization signals in the Sr I 4607 \AA\ spectral line are among the strongest originating from the solar photosphere, offering a powerful diagnostic of tangled magnetic fields in the 3--300 G range via the Hanle effect.…
The physical interpretation of the spectral line polarization produced by the joint action of the Hanle and Zeeman effects offers a unique opportunity to obtain empirical information about hidden aspects of solar and stellar magnetism. To…
The linear polarization pattern produced by scattering processes in the Ca I resonance line at 4227 angstroms is a valuable observable for probing the solar atmosphere. Via the Hanle effect, the very significant Q/I and U/I line-center…
Radiative transfer investigations of the solar Mg II h and k resonance lines around 280~nm showed that, while their circular polarization (Stokes V) signals arise from the Zeeman effect, the linear polarization profiles (Stokes Q and U) are…
Measurements of the ionized Ca II K line are one of the major resources for long-term studies of solar and stellar activity. They also play a critical role in many studies related to solar irradiance variability, particularly as a…
The observed center-to-limb variation (CLV) of the scattering polarization in different lines of the Second Solar Spectrum can be used to constrain the height variation of various atmospheric parameters, in particular the magnetic fields…