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Related papers: A solar-cycle study of coronal rotation: large var…

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The rotation of sunspots of 2 yr in two different solar cycles is studied with the data from the Helioseismic and Magnetic Imager on board the \it Solar Dynamics Observatory \rm and the Michelson Doppler Imager instrument on board the \it…

Solar and Stellar Astrophysics · Physics 2016-07-29 Jianchuan Zheng , Zhiliang Yang , Kaiming Guo , Haimin Wang , Shuo Wang

Although the differential rotation rate on the solar surface has long been studied using optical and extreme ultraviolet (EUV) observations, associating these measurements to specific atmospheric heights remains challenging due to the…

Solar and Stellar Astrophysics · Physics 2025-07-04 Srinjana Routh , Anshu Kumari , Vaibhav Pant , Jaydeep Kandekar , Dipankar Banerjee , Mohd. Saleem Khan , Dibya Kirti Mishra

We obtain scatter broadened images of the Crab Nebula at 80 MHz as it transits through the inner solar wind in June 2016 and 2017. These images are anisotropic, with the major axis oriented perpendicular to the radially outward coronal…

Solar and Stellar Astrophysics · Physics 2017-12-13 K. Sasikumar Raja , Prasad Subramanian , R. Ramesh , Angelos Vourlidas , Madhusudan Ingale

This paper describes a new way of determining the high-latitude solar rotation rate statistically from simultaneous observations of many polar faculae. In this experiment, I extracted frames from a movie made previously from flat-fielded…

Solar and Stellar Astrophysics · Physics 2024-11-05 Neil R. Sheeley

The Sun's internal rotation {\Omega}(r,{\Theta}) has previously been measured using helioseismology techniques and found to be a complex function of co-latitude, {\theta}, and radius, r. From helioseismology and observations of apparently…

Solar and Stellar Astrophysics · Physics 2017-02-08 Ian Cunnyngham , Marcelo Emilio , Jeff Kuhn , Isabelle Scholl , Rock Bush

On 2008 January 10, the twin Solar Terrestrial Relations Observatory (STEREO) A and B spacecraft conducted a high time cadence study of the solar corona with the Extreme UltraViolet Imager (EUVI) instruments with the aim of investigating…

Solar and Stellar Astrophysics · Physics 2010-01-15 M. S. Marsh , R. W. Walsh , S. Plunkett

We analyze data from the Solar and Heliospheric Observatory to produce global maps of coronal outflow velocities and densities in the regions where the solar wind is undergoing acceleration. The maps use UV and white light coronal data…

Solar and Stellar Astrophysics · Physics 2015-06-03 Leonard Strachan , Alexander V. Panasyuk , John L. Kohl , Philippe Lamy

Coronal loops generally trace magnetic lines of force in the upper solar atmosphere. Understanding the loop morphology and its temporal evolution has implications for coronal heating models that rely on plasma heating due to reconnection at…

Solar and Stellar Astrophysics · Physics 2025-01-29 B. Ram , L. P. Chitta , S. Mandal , H. Peter , F. Plaschke

The last solar minimum is characterized by several peculiar aspects and by the presence of a complex magnetic topology with two different kinds of coronal streamers: pseudo-streamers and bipolar streamers. Pseudo-streamers or unipolar…

Solar and Stellar Astrophysics · Physics 2015-07-15 Lucia Abbo , Roberto Lionello , Pete Riley , Yi-Ming Wang

Solar-cycle related variation of differential rotation is investigated through analyzing the rotation rates of magnetic fields, distributed along latitudes and varying with time at the time interval of August 1976 to April 2008. More…

Solar and Stellar Astrophysics · Physics 2015-06-16 K. J. Li , X. J. Shi , J. L. Xie , P. X. Gao , H. F. Liang , L. S. Zhan , W. Feng

Coupled flux transport and magneto-frictional simulations are extended to simulate the continuous magnetic field evolution in the global solar corona for over 15 years, from the start of Solar Cycle 23 in 1996. By simplifying the dynamics,…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. R. Yeates

Parker's initial insights from 1958 provided a key causal link between the heating of the solar corona and the acceleration of the solar wind. However, we still do not know what fraction of the solar wind's mass, momentum, and energy flux…

Astrophysics · Physics 2007-05-23 Steven R. Cranmer

Solar coronal holes are sources of high-speed solar wind streams, which cause persistent geomagnetic activity especially at high latitudes. Here we estimate seasonal solar wind speeds at 1 AU for the last 100 years using high-latitude…

Space Physics · Physics 2017-02-22 Kalevi Mursula , Lauri Holappa , Renata Lukianova

As the solar wind propagates through the heliosphere, dynamical processes irreversibly erase the signatures of the near-Sun heating and acceleration processes. The elemental fractionation of the solar wind should not change during transit…

Solar and Stellar Astrophysics · Physics 2020-08-11 D. Stansby , D. Baker , D. H. Brooks , C. J. Owen

We use helioseismic data from ground and space-based instruments to analyze how solar rotation has changed since the beginning of solar Cycle 23 with emphasis on studying the differences between Cycles 23 and 24. We find that the nature of…

Solar and Stellar Astrophysics · Physics 2019-10-02 Sarbani Basu , H. M. Antia

Helioseismology revealed an increase in the rotation rate with depth just beneath the solar surface. The relative magnitude of the radial shear is almost constant with latitude. This rotational state can be interpreted as a consequence of…

Solar and Stellar Astrophysics · Physics 2016-06-01 Leonid Kitchatinov

The physical processes in the solar corona that shape the solar wind remain an active research topic. Modeling efforts have shown that energy and plasma exchanges near the transition region plays a crucial role in modulating solar wind…

We studied the solar surface flows (differential rotation and meridional circulation) using a magnetic element feature tracking technique by which the surface velocity is obtained using magnetic field data. We used the line-of-sight…

Solar and Stellar Astrophysics · Physics 2018-09-05 Shinsuke Imada , Masashi Fujiyama

Data obtained by the GONG and MDI instruments over the last seven years are used to study how solar dynamics -- both rotation and other large scale flows -- have changed with time. In addition to the well known phenomenon of bands of faster…

Astrophysics · Physics 2009-11-07 Sarbani Basu , H. M. Antia

The variability of helium abundance in the solar corona and the solar wind is an important signature of solar activity, solar cycle, solar wind sources, as well as coronal heating processes. Motivated by recently reported remote sensing UV…

Solar and Stellar Astrophysics · Physics 2024-06-24 Leon Ofman , Yogesh , Silvio Giordano