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Related papers: On the time lag between solar wind dynamic paramet…

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The length of the solar activity cycle fluctuates considerably. The temporal evolution of the corresponding cycle phase, that is, the deviation of the epochs of activity minima or maxima from strict periodicity, provides relevant…

Solar and Stellar Astrophysics · Physics 2023-03-15 E. Weisshaar , R. H. Cameron , M. Schüssler

The main goal of the paper is to explore why observations of many astrospheres (or circumstellar bubbles) show quite stable and smooth structures of astropauses - the tangential discontinuities separating the stellar and interstellar winds,…

Solar and Stellar Astrophysics · Physics 2022-12-13 S. D. Korolkov , V. V. Izmodenov

We study the variability of solar activity using new photospheric proxies originally developed for the analysis of stellar magnetism with the CoRoT and Kepler photometric observations. These proxies are obtained by tracking the temporal…

Solar and Stellar Astrophysics · Physics 2017-12-13 D. Salabert , R. A. García , A Jiménez , L. Bertello , E. Corsaro , P. L. Pallé

We describe the derivation of the InterHourly Variability (IHV) index of geomagnetic activity. The IHV-index for a geomagnetic element is mechanically derived from hourly values as the sum of the unsigned differences between adjacent hours…

Astrophysics · Physics 2015-05-13 Leif Svalgaard , Edward W. Cliver

The variability of the spectral solar irradiance (SSI) over the course of the 11-year solar cycle is one of the manifestations of solar magnetic activity. There is a strong evidence that the SSI variability has an effect on the Earth's…

Solar and Stellar Astrophysics · Physics 2020-04-29 Anna V. Shapiro , Alexander I. Shapiro , Laurent Gizon , Natalie A. Krivova , Sami K. Solanki

The observed persistence of specific periodicities detected in time series associated with solar surface magnetic activity over several solar cycles has led to numerous papers supporting the existence of preferred longitudes. Recent…

Astrophysics · Physics 2007-05-23 C. J. Henney , B. R. Durney

Solar magnetism is measured with different indexes: for instance the MPSI and the MWSI, number of sunspots, radio flux at 10.7 cm, Ca II K, Mg II K, EUV, He I or L_alpha. Bachmann & White (1994) had compared these indicators of the solar…

Astrophysics · Physics 2008-10-13 S. Mathur , S. J. Jimenez-Reyes , R. A. Garcia

The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from January 1, 1945 to December 31, 2010 are used to investigate the temporal variation of the rotational cycle length through the continuous…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. -L. Xie , X. -J. Shi , J. -C. Xu

Wind and solar power are known to be highly influenced by weather events and may ramp up or down abruptly. Such events in the power production influence not only the availability of energy, but also the stability of the entire power grid.…

Data Analysis, Statistics and Probability · Physics 2016-07-20 M. Anvari , G. Lohmann , M. Wächter , P. Milan , E. Lorenz , D. Heinemann , M. Reza Rahimi Tabar , Joachim Peinke

We study the solar-activity and solar-polarity dependence of galactic cosmic-ray intensity (CRI) on the solar and heliospheric parameters playing a significant role in solar modulation. We utilize the data for cosmic-ray intensity as…

Solar and Stellar Astrophysics · Physics 2014-04-07 O. P. M. Aslam , Badruddin

Using the non-linear mean-field dynamo models we calculate the magnetic cycle parameters, like the dynamo cycle period, the amplitude of the total magnetic energy, and the Poynting flux luminosity from the surface for the solar analogs with…

Solar and Stellar Astrophysics · Physics 2021-01-27 V. V. Pipin

Measurement of the solar wind speed near the Sun is important for understanding the acceleration mechanism of the solar wind. In this study, we determine 2D solar wind speeds from 6 to 26 solar radii by applying Fourier motion filters to…

Solar and Stellar Astrophysics · Physics 2018-08-29 Il-Hyun Cho , Yong-Jae Moon , Valery M. Nakariakov , Su-Chan Bong , Jin-Yi Lee , Donguk Song , Harim Lee , Kyung-Suk Cho

We have analysed the Ca-K images obtained at Kodaikanal Observatory as a function of latitude and time for the period of 1913 - 2004 covering the Solar Cycle 15 to 23. We have classified the chromospheric activity into plage, Enhanced…

Solar and Stellar Astrophysics · Physics 2021-03-31 Pooja Devi , Jagdev Singh , Ramesh Chandra , Muthu Priyal , Reetika Joshi

The correlation between geomagnetic activity and the sunspot number in the 11-year solar cycle exhibits long-term variations due to the varying time lag between the sunspot-related and non-sunspot related geomagnetic activity, and the…

Solar and Stellar Astrophysics · Physics 2015-05-18 Katya Georgieva , Boian Kirov

We show that the mean phase of waves propagating all the way from the far side of the Sun to the front side, as measured by seismic holography, varies with time. The change is highly anticorrelated with solar cycle activity and is…

Solar and Stellar Astrophysics · Physics 2009-02-09 I. Gonzalez Hernandez , P. Scherrer , F. Hill

Modulation of galactic cosmic ray intensity is governed by several mechanisms including diffusion, convection, adiabatic energy losses and drift. Relative roles of these factors change in the course of an 11-year solar cycle. That can…

Solar and Stellar Astrophysics · Physics 2014-12-01 G. A. Bazilevskaya , M. S. Kalinin , M. B. Krainev , V. S. Makhmutov , A. K. Svirzhevskaya , N. S. Svirzhevsky

Context. Monitoring of the photometric and chromospheric HK emission data series of stars similar to the Sun in age and average activity level showed that there is an empirical correlation between the average stellar chromospheric activity…

Solar and Stellar Astrophysics · Physics 2015-06-15 A. I. Shapiro , W. Schmutz , G. Cessateur , E. Rozanov

Manifestations of the solar magnetic activity through periodicities of about 11 and 2 years are now clearly seen in all solar activity indices.In this paper, we add information about the mechanism driving the 2 year period by studying the…

Solar and Stellar Astrophysics · Physics 2015-06-11 R. Simoniello , K. Jain , S. C. Tripathy , S. Turck-Chieze , C. Baldner , W. Finsterle , F. Hill , M. Roth

The solar modulation effect of Galactic cosmic rays is a time-dependent phenomenon that is caused by the transport of these particles through the magnetized plasma of the heliosphere. Using a data-driven model of cosmic-ray transport in the…

High Energy Astrophysical Phenomena · Physics 2019-05-22 Miguel Orcinha , Nicola Tomassetti , Fernando Barão , Bruna Bertucci

Solar activity seems quite understandable when considered on the scales comparable with a solar cycle, i.e. about 11 years, and on a short time scale of about a year. A solar cycle looks basically (anti)symmetric with respect to the solar…

Solar and Stellar Astrophysics · Physics 2025-08-08 V. N. Obridko , A. S. Shibalova , D. D. Sokoloff , I. M. Livshits
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