Roberto Casini

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We present a compact, self-consistent formulation for the description of polarized radiation from magnetic-dipole transitions occurring in the magnetized solar corona. This work di †ers from earlier treatments by and House in the 1970s, in that the radiative emission coefficients for the Sahal-Bre chot four Stokes parameters, I, Q, U, and V , are treated(More)
We demonstrate that the atomic alignment of the hyperfine-structure components of the ground level S 1/2 of Na I and of the upper level P 1/2 of the D 1 line are practically negligible for magnetic strengths B > 10 G, and virtually zero for B 100 G. This occurs independently of the magnetic-field inclination on the stellar surface (in particular, also for(More)
We present the first theoretical, forward calculations of the Stokes profiles of several magnetic dipole (''M1'') coronal emission lines produced in current-carrying magnetic structures. An idealized coronal model of Low, Fong, and Fan is used, which describes a spherically symmetric, hydrostatic background atmosphere, isothermal at a coronal temperature of(More)
The purpose of this note is to determine the maximum level of polarimetric noise that can be tolerated when performing filter polarimetry of the He I lines at 5876Å and 10830Å. The objective is to ensure that their Stokes parameters still carry enough information for an acceptable magnetic inversion. The simulations reported in this Note cover the cases of(More)
We investigate the use of Terahertz (THz) Time Domain Spectroscopy (TDS) as a tool for the measurement of the index dispersion of multi-walled carbon nanotubes (MWCNT) in polypropylene (PP) based composites. Samples containing 0.5% by volume concentration of non-functionalized and functionalized carbon nanotubes are prepared by melt compounding technology.(More)
Information about the three-dimensional structure of solar magnetic fields is encoded in the polarized spectra of solar radiation by a host of physical processes. To extract this information, solar spectra must be obtained in a variety of magnetically sensitive spectral lines at high spatial, spectral, and temporal resolution with high precision. The need(More)
For about a decade, spectro-polarimetry of He I λ10830 has been applied to the magnetic diagnostics of the solar chromosphere. This resonance line is very versatile, as it is visible both on disk and in off-limb structures, and it has a good sensitivity to both the weak-field Hanle effect and the strong-field Zeeman effect. Recent observations of an(More)