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Observations of magnetic helicity transportation through the solar photosphere reflect the interaction of turbulent plasma movements and magnetic fields in the solar dynamo process. In this chapter, we have reviewed the research process of…

Solar and Stellar Astrophysics · Physics 2023-11-14 Hongqi Zhang , Shangbin Yang , Haiqing Xu , Xiao Yang , Jie Chen , Jihong Liu

Long (up to 100 hours) time series of SOHO/MDI Doppler data are analyzed. The power spectrum of radial velocity time series in the quiet photosphere is observed to have, along with the known 5-min mode, a stable strong mode with a period of…

Solar and Stellar Astrophysics · Physics 2014-12-08 L. D. Parfinenko , V. I. Efremov , A. A. Solovev

Here, we present several examples of unusual evolutionary patterns in solar coronal loops that resemble cross-field drift motions. These loops were simultaneously observed from two vantage points by two different spacecraft: the…

Solar and Stellar Astrophysics · Physics 2025-05-28 Sudip Mandal , Hardi Peter , James A. Klimchuk , Lakshmi Pradeep Chitta

Although the interplanetary magnetic field variability has been extensively investigated in situ by means of data coming from several space missions, the newly launched missions providing high-resolution measures and approaching the Sun,…

Magneto-convection simulations on meso-granule and granule scales near the solar surface are used to study small scale dynamo activity, the emergence and disappearance of magnetic flux tubes, and the formation and evolution of micropores.…

Astrophysics · Physics 2007-05-23 Robert F. Stein , Aake Nordlund

Solar inertial modes have the potential to surpass the diagnostic capabilities of acoustic waves in probing the deep interior of the Sun. The fulfillment of this potential requires an accurate identification and characterization of these…

Solar and Stellar Astrophysics · Physics 2025-03-20 Chris S. Hanson , Vivek Menon , Shravan Hanasoge , Katepalli R. Sreenivasan

We derive horizontal fluid motions on the solar surface over large areas covering the quiet-Sun magnetic network from local correlation tracking of convective granules imaged in continuum intensity and Doppler velocity by the Helioseismic…

Solar and Stellar Astrophysics · Physics 2016-06-29 C. R. Sangeetha , S. P. Rajaguru

The differential rotation of the sun, as deduced from helioseismology, exhibits a prominent radial shear layer near the top of the convection zone wherein negative radial gradients of angular velocity are evident in the low- and…

Astrophysics · Physics 2009-11-07 M. L. DeRosa , P. A. Gilman , J. Toomre

Stellar surface magnetoconvection (granulation) creates asymmetries in the observed stellar absorption lines that can subsequently manifest themselves as spurious radial velocities shifts. In turn, this can then mask the Doppler-reflex…

Earth and Planetary Astrophysics · Physics 2019-07-10 H. M. Cegla , C. A. Watson , S. Shelyag , M. Mathioudakis , S. Moutari

The Sun's magnetic dynamo cycle features a distinct pattern: a propagating region of sunspot emergence appears around 30 degrees latitude and vanishes near the equator every 11 years. Moreover, longitudinal flows called "torsional…

In this work, we have studied the temporal evolution of some properties of a sample of superactive regions with the aim to single out the most significant for flare activity forecasting. We have investigated properties of 14 superactive…

Solar and Stellar Astrophysics · Physics 2015-05-14 S. Criscuoli , P. Romano , F. Zuccarello , F. Giorgi

Context: Solar sectoral Rossby waves have only recently been unambiguously identified in Helioseimsic and Magnetic Imager (HMI) and Michelson Doppler Imager (MDI) maps of flows near the solar surface. So far this has not been done with the…

Solar and Stellar Astrophysics · Physics 2020-03-18 Chris S. Hanson , Laurent Gizon , Zhi-Chao Liang

Time-distance helioseismology provides information about vector flows in the near-surface layers of the Sun by measuring wave travel times between points on the solar surface. Specific spatial averages of travel times have been proposed for…

Solar and Stellar Astrophysics · Physics 2015-01-05 Jan Langfellner , Laurent Gizon , Aaron C. Birch

We report the results of a magneto-hydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field…

Solar and Stellar Astrophysics · Physics 2014-06-18 Yuhong Fan , Fang Fang

We present and discuss the strong correspondence between evolution of the emission length scale in the lower transition region and in situ measurements of the fast solar wind composition during this most recent solar minimum. We combine…

Solar and Stellar Astrophysics · Physics 2015-05-30 Scott W. McIntosh , Kandace K. Kiefer , Robert J. Leamon , Justin C. Kasper , Michael S. Stevens

Context. Large-amplitude inversions of the solar wind's interplanetary magnetic field have long been documented; however, observations from the Parker Solar Probe (PSP) mission have renewed interest in this phenomenon as such features,…

Velocity oscillations "measured" simultaneously at the photosphere and the chromosphere -from time series of spectropolarimetric data in the 10830 A region- of different solar magnetic features allow us to study the properties of wave…

Astrophysics · Physics 2011-02-11 Rebecca Centeno , Manuel Collados , Javier Trujillo Bueno

The operation of the solar global dynamo appears to involve many dynamical elements. Self-consistent MHD simulations which realistically incorporate all of these processes are not yet computationally feasible, though some elements can now…

Astrophysics · Physics 2008-11-26 Allan Sacha Brun , Mark S. Miesch , Juri Toomre

The mechanism and characteristics of the irregular variations of red supergiants (RSGs) are studied based on the RSG samples in Small Magellanic Cloud (SMC), Large Magellanic Cloud (LMC) and M31. With the time-series data from All-Sky…

Solar and Stellar Astrophysics · Physics 2020-07-29 Yi Ren , B. W. Jiang

On the base of the solar magnetic field measurements obtained in Stanford in 1976--2003 the properties of the cyclic evolution of the large-scale magnetic field are investigated. Some regularities are found in longitudinal and latitudinal…

Astrophysics · Physics 2007-05-23 R. N. Ikhsanov , V. G. Ivanov
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