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The differential rotation of the solar corona for the period 1976-2004 was studied as a function of the distance from the center of the Sun. For this study, we developed a method using the coronal magnetic field as a tracer. The field in a…

太阳与恒星天体物理 · 物理学 2018-09-19 O. G. Badalyan , V. N. Obridko

Helioseismology has revealed that the angular velocity of the Sun increases with depth in the outermost 35 Mm of the Sun. Recently, we have shown that the logarithmic radial gradient ($\rm d\ln\Omega/\rm d\ln r $) in the upper 10~Mm is…

太阳与恒星天体物理 · 物理学 2016-11-02 Atefeh Barekat , Jesper Schou , Laurent Gizon

Decayless kink oscillations of solar coronal loops (or decayless oscillations for short) have attracted great attention since their discovery. Coronal bright points (CBPs) are mini-active regions and consist of loops with a small size.…

太阳与恒星天体物理 · 物理学 2022-05-18 Yuhang Gao , Hui Tian , Tom Van Doorsselaere , Yajie Chen

We present a comprehensive analysis of Solar Cycle 25 aimed at precisely constraining the interval of its activity maximum using multiple observational parameters: sunspot number (SSN), Wolf number, the 10.7 cm solar radio flux (F10.7), the…

太阳与恒星天体物理 · 物理学 2025-11-24 Homer Dávila Gutiérrez

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…

太阳与恒星天体物理 · 物理学 2017-02-28 Hitaishi Bhatt , Rupal Trivedi , Som Kumar Sharma , Hari Om Vats

The global rotational profile of the solar atmosphere and its variation at different layers, although crucial for a comprehensive understanding of the dynamics of the solar magnetic field, has been a subject to contradictory results…

The minimum of solar cycle 24 is significantly different from most other minima in terms of its duration as well as its abnormally low levels of activity. Using available helioseismic data that cover epochs from the minimum of cycle 23 to…

太阳与恒星天体物理 · 物理学 2015-05-19 H. M. Antia , Sarbani Basu

We investigate periodicities in mean heliographic latitudes of sunspot groups, called active latitudes, for the last six complete solar cycles (1945-2008). For this purpose, the Multi Taper Method and Morlet Wavelet analysis methods were…

太阳与恒星天体物理 · 物理学 2023-01-06 A. Kilcik , V. Yurchyshyn , F. Clette , A. Ozguc , J. -P. Rozelot

Three dimensional electron density distributions in the solar corona are reconstructed for 100 Carrington Rotations (CR 2054$-$2153) during 2007/03$-$2014/08 using the spherically symmetric method from polarized white-light observations…

太阳与恒星天体物理 · 物理学 2017-07-25 Tongjiang Wang , Nelson L. Reginald , Joseph M. Davila , O. Chris St. Cyr , William T. Thompson

The goal of this paper is to investigate Reynolds stresses and to check if it is plausible that they are responsible for angular momentum transfer toward the solar equator. We also analysed meridional velocity, rotation velocity residuals…

太阳与恒星天体物理 · 物理学 2014-03-05 D. Sudar , I. Skokić , D. Ruždjak , R. Brajša , H. Wöhl

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…

太阳与恒星天体物理 · 物理学 2015-05-27 Hari Om Vats , Satish Chandra

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.…

太阳与恒星天体物理 · 物理学 2021-05-28 Vivek Kumar Singh , Satish Chandra , Sanish Thomas , Som Kumar Sharma , Hari Om Vats

We study solar differential rotation (DR) for solar cycle No. 19 (1954-1964) by tracing sunspot groups on the sunspot drawings of Kanzelhoehe Observatory for Solar and Environmental Research (KSO). Our aim is to extend previous DR analysis…

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…

太阳与恒星天体物理 · 物理学 2019-12-17 Caius L. Selhorst , Juha Kallunki , C. G. Giménez de Castro , Adriana Valio , Joaquim E. R. Costa

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…

太阳与恒星天体物理 · 物理学 2024-11-28 N. B. Xiang , X. H. Zhao , L. H. Deng , F. Y. Li , Y. J. Wang , X. W. Tan

This research work is based on the study of the longitudinal distribution of the most active sunspot zones on the photosphere. Sunspot data has been analyzed for 12 solar cycles (cycles 12-23) separately for northern and southern…

太阳与恒星天体物理 · 物理学 2009-09-17 Abdul Malik , Martin Bohm

We analyzed the combined 142 years sunspot-group data from Greenwich Photoheliograpic Results (GPR) and Debrecen Photoheliographic Data (DPD) and determined the yearly mean residual rotation rate and the meridional velocity of sunspot…

太阳与恒星天体物理 · 物理学 2021-09-22 J. Javaraiah

We study a sample of 21 young and active solar-type stars with spectral types ranging from late F to mid K and characterize the behaviour of their activity. We apply the continuous period search (CPS) time series analysis method on 16 to 27…

太阳与恒星天体物理 · 物理学 2016-03-21 Jyri Lehtinen , Lauri Jetsu , Thomas Hackman , Perttu Kajatkari , Gregory W. Henry

On the Sun, the rotation periods of individual sunspots not only trace the latitude dependence of the surface rotation rate, but also provide clues as to the amount of subsurface fluid shear. In this paper we present the first measurements…

天体物理学 · 物理学 2009-11-07 A. Collier Cameron , J. -F. Donati , M. Semel

The analysis of the rotation rate of individual sunspots and pores was performed according to the data of the processing of observations by the \textit{Solar Dynamics Observatory/Helioseismic and Magnetic Imager} (SDO/HMI) in the period…

太阳与恒星天体物理 · 物理学 2024-11-12 Andrei G. Tlatov , Kseniia A. Tlatova