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Related papers: A long term multi-frequency study of solar rotatio…

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The present study is an attempt to investigate the long term variations in coronal rotation by analyzing the time series of the solar radio emission data at 2.8 GHz frequency for the period 1947 - 2009. Here, daily adjusted radio flux…

Solar and Stellar Astrophysics · Physics 2015-05-27 Satish Chandra , Hari Om Vats

The present work is an effort to investigate possible radial variations in the solar coronal rotation by analyzing the solar radio emission data at 15 different frequencies (275-1755 MHz) for the period starting from July 1994 to May 1999.…

Solar and Stellar Astrophysics · Physics 2021-05-28 Vivek Kumar Singh , Satish Chandra , Sanish Thomas , Som Kumar Sharma , Hari Om Vats

The daily measurements of the disc-integrated solar radio flux, observed by the Radio Solar Telescope Network (RSTN), at 245, 410, 610, 1415, 2695, 4995, and 8800 MHz during the time interval of 1989 January 1 to 2019 December 17, are used…

Solar and Stellar Astrophysics · Physics 2024-11-28 N. B. Xiang , X. H. Zhao , L. H. Deng , F. Y. Li , Y. J. Wang , X. W. Tan

Using the Hilbert-Huang transform technique, we investigate the midrange periodicities in solar radio flux at 2800 MHz (F10.7) and sunspot areas (SAs) from February 1, 1947 to September 30, 2016. The following prominent results are found:…

Solar and Stellar Astrophysics · Physics 2018-11-21 Ying Mei , Hui Deng , Feng Wang

Available helioseismic data now span almost the entire solar activity cycle 23 making it possible to study solar-cycle related changes of the solar rotation rate in detail. In this paper we study how the solar rotation rate, in particular,…

Astrophysics · Physics 2009-11-13 H. M. Antia , Sarbani Basu , S. M. Chitre

Temporal variation of the solar coronal rotation appears to be very complex and its relevances to the eleven-year solar activity cycle are still unclear. Using the modified coronal index for the time interval from 1939 January 1 to 2019 May…

Solar and Stellar Astrophysics · Physics 2020-01-08 L. H. Deng , X. J. Zhang , H. Deng , Y. Mei , F. Wang

The structure of electric current and magnetic helicity in the solar corona is closely linked to solar activity over the 11-year cycle, yet is poorly understood. As an alternative to traditional current-free "potential field"…

Solar and Stellar Astrophysics · Physics 2015-05-18 A. R. Yeates , J. A. Constable , P. C. H. Martens

We investigate the characteristics and the sources of the slow (< 450 km/s) solar wind during the four years (2006-2009) of low solar activity between Solar Cycles 23 and 24. We use a comprehensive set of in-situ observations in the…

Solar and Stellar Astrophysics · Physics 2016-10-05 E. K. J. Kilpua , M. S. Madjarska , N. Karna , T. Wiegelmann , C. Farrugia , W. Yu , K. Andreeova

Here we report in depth reanalysis of a paper by Vats et al. (2001) [Astrophys. J. 548, L87] based on the measurements of differential rotation with altitude as a function of observing frequencies (as lower and higher frequencies indicate…

Solar and Stellar Astrophysics · Physics 2017-02-28 Hitaishi Bhatt , Rupal Trivedi , Som Kumar Sharma , Hari Om Vats

Rotation is a prominent feature of the Sun, and it plays a crucial role in the generation and dynamic evolution of solar magnetic fields. The daily composite time series of Ca II K plage areas from 1907 February 1 to 2023 December 31 is…

Solar and Stellar Astrophysics · Physics 2025-12-18 N. B. Xiang , X. H. Zhao , L. H. Deng , F. Y. Li , M. Wan , S. Y. Qi

Analysis of over 36 years of time series data from the NSO/AFRL/Sac Peak K-line monitoring program elucidates five components of the variation of the seven measured chromospheric parameters: (a) the solar cycle (period ~ 11 years), (b)…

Solar and Stellar Astrophysics · Physics 2015-06-15 Jeffrey Scargle , Stephen Keil , Pete Worden

To better understand the influence of the activity cycle on the solar atmosphere, we report the time variation of the radius observed at 37 GHz ($\lambda$=8.1 mm) obtained by the Mets\"ahovi Radio Observatory (MRO) through Solar Cycles 22…

Solar and Stellar Astrophysics · Physics 2019-12-17 Caius L. Selhorst , Juha Kallunki , C. G. Giménez de Castro , Adriana Valio , Joaquim E. R. Costa

Three types of observations: the daily values of the solar radio flux at 7 frequencies, the daily international sunspot number and the daily Stanford mean solar magnetic field were processed in order to find all the periodicities hidden in…

Astrophysics · Physics 2009-11-07 S. Zieba , J. Maslowski , A. Michalec , A. Kulak

Convection, differential rotation, and meridional circulation of solar plasma are studied based on helioseismic data covering the period from May 2010 to August 2024, significantly prolonged compared to that previously considered. Depth…

Solar and Stellar Astrophysics · Physics 2025-04-22 A. V. Getling , A. G. Kosovichev

Understanding coronal structure and dynamics can be facilitated by analyzing green-line emission, which enables the investigation of diverse coronal structures such as coronal loops, streamers, coronal holes, and various eruptions in the…

Solar and Stellar Astrophysics · Physics 2024-11-27 Jacob Oloketuyi , Yu Liu , Linhua Deng , Abouazza Elmhamdi , Fengrong Zhu , Ayodeji Ibitoye , Opeyemi Omole , Feiyang Sha , Qiang Liu

Rotation is a significant characteristic of the Sun and other stars, and it plays an important role in understanding their dynamo actions and magnetic activities. In this study, the rotation of the solar chromospheric activity is…

Solar and Stellar Astrophysics · Physics 2020-10-22 Jing-Chen Xu , Peng-Xin Gao , Xiang-Jun Shi

The temporal variations of the rotation rate in the solar interior are studied using frequency splittings from Global Oscillations Network Group (GONG) data obtained during the period 1995-99. We find alternating latitudinal bands of faster…

Astrophysics · Physics 2009-10-31 H. M. Antia , Sarbani Basu

I study the sunspot area fluctuations over the epoch of 12 solar cycles (12-23). Lately, I found three significant quasi-periodicities at 10, 17 and 23 solar rotations, but two longer periods could be treated as subharmonics of the…

Applications · Statistics 2010-05-24 R. Getko

We investigate spatio-temporal evolution of high-degree acoustic mode frequencies of the Sun and the surface magnetic activity, over the course of multiple solar cycles, to improve our understanding of the connection between the solar…

Solar and Stellar Astrophysics · Physics 2023-12-20 Mackenzie A. Baird , Sushanta C. Tripathy , Kiran Jain

The solar images at 17 GHz by Nobeyama Radio Heliograph and in X-ray by soft X-ray telescope (SXT) on board Yohkoh satellite have been of particular interest for the estimation of solar coronal rotation using flux modulation approach. These…

Solar and Stellar Astrophysics · Physics 2015-05-27 Hari Om Vats , Satish Chandra
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