The Nonlinear Hanle Effect and Its Applications to Laser Physics

Moruzzi, G.; Strumia, F.; Beverini, N.

doi:10.1007/978-1-4615-3826-4_4

Cited by 12 publications

(14 citation statements)

References 177 publications

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“…Special attention has been given, observationally and theoretically, to the influence of weak or tangled magnetic fields on resonance line polarization through the Hanle effect (Moruzzi & Strumia 1991), which has opened a new diagnostic window for the magnetism in the solar atmosphere (e.g., Stenflo 1982Stenflo , 1991Leroy 1989;Bommier et al 1994;Faurobert-Scholl 1993;Faurobert-Scholl et al 1995;Lin et al 1998;Trujillo Bueno 2001;Trujillo Bueno & Manso Sainz 2002;López Ariste & Casini 2005;Trujillo Bueno et al 2005). By contrast, elastic depolarizing collisions have received relatively little attention in this context, motivated by their apparent lack of diagnostic value.…”

Section: Introductionmentioning

confidence: 99%

Depolarizing Collisions With Hydrogen: Neutral and Singly Ionized Alkaline Earths

Sainz

Roncero

Sanz-Sanz

et al. 2014

ApJ

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Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg i, Sr i, Ba i, Mg ii, Ca ii, and Ba ii, due to collisions with H • . We compute ab initio potential curves of the atom-H • system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T 10,000 K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.

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Section: Introductionmentioning

confidence: 99%

Depolarizing Collisions With Hydrogen: Neutral and Singly Ionized Alkaline Earths

Sainz

Roncero

Sanz-Sanz

et al. 2014

ApJ

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“…The Hanle effect is a weak field case of the Zeeman effect with consequence for resonance line scattering polarization in the presence of a magnetic field (e.g., Moruzzi & Strumia 1991;Stenflo 1994;Landi Degl' Innocenti & Landolfi 2004). The Hanle effect describes the influence of the field for the linear polarization of line scattering; unlike the Zeeman effect, the Hanle effect does not generate circularly polarized emissions.…”

Section: Introductionmentioning

confidence: 99%

Time-dependent behavior of linear polarization in unresolved photospheres, with applications for the Hanle effect

Ignace

Hole

Cassinelli

et al. 2011

A&A

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Aims. This paper extends previous studies in modeling time varying linear polarization due to axisymmetric magnetic fields in rotating stars. We use the Hanle effect to predict variations in net line polarization, and use geometric arguments to generalize these results to linear polarization due to other mechanisms. Methods. Building on the work of Lopez Ariste et al. (2011, A&A, 527, A120), we use simple analytic models of rotating stars that are symmetric except for an axisymmetric magnetic field to predict the polarization lightcurve due to the Hanle effect. We highlight the effects for the variable line polarization as a function of viewing inclination and field axis obliquity. Finally, we use geometric arguments to generalize our results to linear polarization from the weak transverse Zeeman effect. Results. We derive analytic expressions to demonstrate that the variable polarization lightcurve for an oblique magnetic rotator is symmetric. This holds for any axisymmetric field distribution and arbitrary viewing inclination to the rotation axis. Conclusions. For the situation under consideration, the amplitude of the polarization variation is set by the Hanle effect, but the shape of the variation in polarization with phase depends largely on geometrical projection effects. Our work generalizes the applicability of results described in Lopez Ariste et al., inasmuch as the assumptions of a spherical star and an axisymmetric field are true, and provides a strategy for separating the effects of perspective from the Hanle effect itself for interpreting polarimetric lightcurves.

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“…Coherent population trapping (CPT) [1,2], electromagnetically induced transparency (EIT) [3], and electromagnetically induced absorption (EIA) [4,5] have been observed and examined in pump-probe and in the Hanle configuration [6]. All these effects nonlinearly depend on intensity of the applied laser field.…”

Section: Introductionmentioning

confidence: 99%