Low frequency radio observations of the `quiet' corona during the descending phase of sunspot cycle 24

Abstract

We carried out a statistical study of the `quiet' solar corona during the descending phase of the sunspot cycle 24 (i.e. 2015 January - 2019 May) using data obtained with the Gauribidanur RAdioheliograPH (GRAPH) at 53 MHz and 80 MHz simultaneously. Our results show that the equatorial (east-west) diameters of the solar corona at the above two frequencies shrunk steadily. The decrease was found to be due to a gradual reduction in the coronal electron density ($N_e$). Independent estimates of $N_e$ in the equatorial region of the `background' corona using white-light coronagraph observations indicate a decline consistent with our findings.

Accepted for publication in Geophysical Research Letters

References in corpus (5)

• Low frequency observations of transient quasi-periodic radio emission from the solar atmosphere
• Validation of Spherically Symmetric Inversion by Use of a Tomographic Reconstructed Three-Dimensional Electron Density of the Solar Corona
• Amplitude of solar wind density turbulence from 10--45 $R_{\odot }$
• Variation of Coronal Activity from the Minimum to Maximum of Solar Cycle 24 using Three Dimensional Coronal Electron Density Reconstructions from STEREO/COR1
• Design and performance of a low frequency cross-polarized log-periodic dipole antenna

Cited by in corpus (4)

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• Radio Interferometric Observations of the Sun Using Commercial Dish TV Antennas
• Radio, X-ray and extreme-ultraviolet observations of weak energy releases in the `quiet' Sun