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arXiv · 2009.02670

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

R. Ramesh·A. Kumari·C. Kathiravan·D. Ketaki·M. Rajesh·M. Vrunda
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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.

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R. Ramesh, A. Kumari, C. Kathiravan, D. Ketaki, M. Rajesh, M. Vrunda. 2020-09-06. Low frequency radio observations of the `quiet' corona during the descending phase of sunspot cycle 24. https://doi.org/10.1029/2020gl090426

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