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 to(More)
We demonstrate that the atomic alignment of the hyperfine-structure components of the ground level S1/2 of Na I and of the upper level P1/2 of the D1 line are practically negligible for magnetic strengths B > 10G, and virtually zero for B & 100G. This occurs independently of the magnetic-field inclination on the stellar surface (in particular, also for(More)
Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden(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)
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)
Measurements of components of the vector magnetic eld in the solar corona can potentially yield information critical to our understanding of coronal structure dynamics and heating In this report we re examine various techniques for such measurements in particular those that can be applied outside of active regions to investigate issues critical to the(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)
We derive from first principles the expression for the angular/wavelength distribution of the intensity diffracted by a blazed reflective grating, according to a scalar theory of diffraction. We considered the most common case of a groove profile with rectangular apex. Our derivation correctly identifies the geometric parameters of a blazed reflective(More)