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Variability observed in photometric lightcurves of late-type stars (on timescales longer than a day) is a dominant noise source in exoplanet surveys and results predominantly from surface manifestations of stellar magnetic activity, namely…

Time series of photospheric magnetic parameters of solar active regions (ARs) are used to answer whether scaling properties of fluctuations embedded in such time series help to distinguish between flare-quiet and flaring ARs. We examine a…

Solar and Stellar Astrophysics · Physics 2020-10-21 Eo-Jin Lee , Sung-Hong Park , Yong-Jae Moon

While photospheric magnetic elements appear mainly as Bright Points (BPs) at the disk center and as faculae near the limb, high-resolution images reveal the coexistence of BPs and faculae over a range of heliocentric angles. This is not…

Solar and Stellar Astrophysics · Physics 2010-01-29 P. Kobel , J. Hirzberger , S. K. Solanki , A. Gandorfer , V. Zakharov

Magnetic elements of the solar surface are studied in magnetograms recorded with the high-resolution Solar Dynamics Observatory / Helioseismic and Magnetic Imager . To extract some statistical and physical properties of these elements…

Solar and Stellar Astrophysics · Physics 2017-07-31 Mohsen Javaherian , Hossein Safari , Neda Dadashi , Markus Josef Aschwanden

We present and analyze FUSE observations of six solar analogs. These are single, main-sequence G0-5 strs selected as proxies for the Sun at several stages of its main-sequence lifetime. The emission features in the FUSE 920-1180 A…

Astrophysics · Physics 2009-11-07 Edward F. Guinan , Ignasi Ribas , Graham M. Harper

Global magnetic field models use as input synoptic data, which usually show "aging effects" as the longitudinal 360{\deg} information is not obtained simultaneously. Especially during times of increased solar activity, the evolution of the…

Solar and Stellar Astrophysics · Physics 2021-10-04 Stephan G. Heinemann , Manuela Temmer , Stefan J. Hofmeister , Aleksandar Stojakovic , Laurent Gizon , Dan Yang

This work focus on the first results on the identification and characterization of periodic plasma density fluctuations in the outer corona, observed in STEREO-A COR1 white-light image time series. A 2D reconstruction of the spatial…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. Telloni , R. Ventura , P. Romano , D. Spadaro , E. Antonucci

A new method for automated detection of polar coronal holes is presented. This method, called perimeter tracing, uses a series of 171, 195, and 304 \AA\ full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO over…

Solar and Stellar Astrophysics · Physics 2015-05-13 Michael S. Kirk , W. Dean Pesnell , C. Alex Young , Shea A. Hess Webber

In this paper, we investigate the inhomogeneous spatial distribution of solar faculae. The focus is on the latitudinal and longitudinal distributions of these highly localised features covering ubiquitously the solar surface. The…

Solar and Stellar Astrophysics · Physics 2018-08-22 A. Elek , N. Gyenge , M B. Korsós , R. Erdélyi

A magnetic power spectral analysis is performed on 53 solar active regions, observed from August 2011 to July 2012. Magnetic field data obtained from the Helioseismic and Magnetic Imager, inverted as Active Region Patches, are used to study…

Solar and Stellar Astrophysics · Physics 2016-12-28 Revati S. Mandage , R. T. James McAteer

This work is devoted to investigation of low frequency variations in Polar motion (PM). It has been shown that the main PM features can be effectively investigated using not only time series of the Pole coordinates, but also using series of…

Geophysics · Physics 2013-12-09 N. Miller , Z. Malkin

Measurements of the large cellular flows on the Sun were made by local correlation tracking of supergranules seen in full-disk Doppler images obtained by the HMI instrument on the NASA SDO satellite. The hourly measurements were averaged…

Solar and Stellar Astrophysics · Physics 2021-02-24 David H. Hathaway , Lisa A. Upton

Photospheric vector magnetograms from Helioseismic and Magnetic Imager on board the Solar Dynamic Observatory are utilized as the boundary conditions to extrapolate both non-linear force-free and potential magnetic fields in solar corona.…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. T. Su , J. Jing , S. Wang , T. Wiegelmann , H. M. Wang

Context: Studying the motions on the solar surface is fundamental for understanding how turbulent convection transports energy and how magnetic fields are distributed across the solar surface. Aims: From horizontal velocity measurements all…

Solar and Stellar Astrophysics · Physics 2015-06-22 Th. Roudier , M. Švanda , M. Rieutord , J. M. Malherbe , R. Burston , L. Gizon

Magnetic helicity is a key geometrical parameter to describe the structure and evolution of solar coronal magnetic fields. The accumulation of magnetic helicity is correlated with the non-potential magnetic field energy, which is released…

Solar and Stellar Astrophysics · Physics 2024-12-25 Shangbin Yang , Suo Liu , Jiangtao Su , Yuanyong Deng

We have been monitoring yearly variation in the Sun's polar magnetic fields with the Solar Optical Telescope aboard {\it Hinode} to record their evolution and expected reversal near the solar maximum. All magnetic patches in the magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-05 D. Shiota , S. Tsuneta , M. Shimojo , N. Sako , D. Orozco Suárez , R. Ishikawa

The Sun's surface field, especially the polar field, sets the boundary condition for the coronal and heliospheric magnetic fields, but also provides us insight into the dynamo process. The evolution of the polar fields results from the…

Solar and Stellar Astrophysics · Physics 2018-07-05 Jie Jiang , Jinbin Cao

Two populations of twisted magnetic field tubes, or flux ropes (hereafter, FRs), are detected by in situ measurements in the solar wind. While small FRs are crossed by the observing spacecraft within few hours, with a radius typically less…

Solar and Stellar Astrophysics · Physics 2015-06-22 M. Janvier , P. Demoulin , S. Dasso

Solar post-flare loops (PFLs) are arcade-like loop systems that appear during the gradual phases of eruptive flares. The extreme ultraviolet (EUV) observations from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2016-04-27 Qiao Song , Jing-Song Wang , Xueshang Feng , Xiaoxin Zhang