Sizes and Shapes of Sources in Solar Metric Radio Bursts - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue The Astrophysical Journal Année : 2022

Sizes and Shapes of Sources in Solar Metric Radio Bursts

Résumé

Metric and decametric radio emissions from the Sun are the only direct source of information about the dynamics of nonthermal electrons in the upper corona. In addition, the combination of spectral and imaging (sizes, shapes, and positions) observations of low-frequency radio sources can be used as a unique diagnostic tool to probe plasma turbulence in the solar corona and inner heliosphere. The geometry of the low-frequency sources and its variation with frequency are still not understood, primarily due to the relatively low spatial resolution available for solar observations. Here we report the first detailed multifrequency analysis of the sizes of solar radio sources observed by the Low Frequency Array. Furthermore, we investigate the source shapes by approximating the derived intensity distributions using 2D Gaussian profiles with elliptical half-maximum contours. These measurements have been made possible by a novel empirical method for evaluating the instrumental and ionospheric effects on radio maps based on known source observations. The obtained deconvolved sizes of the sources are found to be smaller than previous estimations, and often show higher ellipticity. The sizes and ellipticities of the sources inferred using 2D Gaussian approximation, and their variation with frequency are consistent with models of anisotropic radio-wave scattering in the solar corona.

Mots clés

Fichier principal
Vignette du fichier
Gordovskyy_2022_ApJ_925_140.pdf (3.58 Mo) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-03561414 , version 1 (08-02-2022)

Identifiants

Citer

Mykola Gordovskyy, Eduard P Kontar, Daniel L Clarkson, Nicolina Chrysaphi, Philippa K Browning. Sizes and Shapes of Sources in Solar Metric Radio Bursts. The Astrophysical Journal, 2022, 925 (2), pp.140. ⟨10.3847/1538-4357/ac3bb7⟩. ⟨hal-03561414⟩
18 Consultations
18 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More