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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Thyr: a volumetric ray-marching tool for simulating microwave emission

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Osborne, Christopher M. J. [1] ; Simoes, Paulo J. A. [2, 3, 1]
Total Authors: 2
[1] Univ Glasgow, Sch Phys & Astron, SUPA, Glasgow G12 8QQ, Lanark - Scotland
[2] Univ Presbiteriana Mackenzie, Escola Engn, BR-01302907 Sao Paulo, SP - Brazil
[3] Univ Presbiteriana Mackenzie, CRAAM, BR-01302907 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Monthly Notices of the Royal Astronomical Society; v. 485, n. 3, p. 3386-3397, MAY 2019.
Web of Science Citations: 0

Gyrosynchrotron radiation is produced by solar flares, and can be used to infer properties of the accelerated electrons and magnetic field of the flaring region. This microwave emission is highly dependent on many local plasma parameters, and the viewing angle. To correctly interpret observations, detailed simulations of the emission are required. Additionally, gyrosynchrotron emission from the chromosphere has been largely ignored in modelling efforts, and recent studies have shown the importance of thermal emission at millimetric wavelengths. Thyr is a new tool for modelling microwave emission from three-dimensional flaring loops with spatially varying atmosphere and increased resolution in the lower corona and chromosphere. Thyr is modular and open-source, consisting of separate components to compute the thermal and non-thermal microwave emission coefficients and perform three-dimensional radiative transfer (in local thermodynamic equilibrium). The radiative transfer integral is computed by a novel ray-marching technique to efficiently compute the contribution of many volume elements. This technique can also be employed on a variety of astrophysics problems. Herein we present a review of the theory of gyrosynchrotron radiation, and two simulations of identical flare loops in low-and high resolution performed with Thyr, with a spectral imaging analysis of differing regions. The high-resolution simulation presents a spectral hardening at higher frequencies. This hardening originates around the top of the chromosphere due to the strong convergence of the magnetic field, and is not present in previous models due to insufficient resolution. This hardening could be observed with a coordinated flare observation from active radio observatories. (AU)

FAPESP's process: 08/09339-2 - Analysis of the time evolution of radio emission of solar flares in inhomogeneous environment
Grantee:Paulo José de Aguiar Simões
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 09/18386-7 - Integrated modelling of radio and X-ray emission during solar flares
Grantee:Carlos Guillermo Giménez de Castro
Support type: Regular Research Grants
FAPESP's process: 03/03406-6 - Gyrosynchrotron radiation of solar flares in complex magnetic field environments
Grantee:Paulo José de Aguiar Simões
Support type: Scholarships in Brazil - Master
FAPESP's process: 04/14248-5 - Dynamic spatial distribution of electrons in solar flares
Grantee:Paulo José de Aguiar Simões
Support type: Scholarships in Brazil - Doctorate