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

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In this paper, we study two sets of local geomagnetic indices from 26 stations using the principal component (PC) and the independent component (IC) analysis methods. We demonstrate that the annually averaged indices can be accurately…

Solar and Stellar Astrophysics · Physics 2015-01-16 Lauri Holappa , Kalevi Mursula , Timo Asikainen

The frequency spectrum of the hemispheric asymmetry of solar activity shows enhanced power for the period ranges around 8.5 years and between 30 and 50 years. This can be understood as the sum and beat periods of the superposition of two…

Solar and Stellar Astrophysics · Physics 2018-10-17 M. Schüssler , R. H. Cameron

The photometric time series of solar-like stars can exhibit rotational modulation due to active regions co-rotating with the stellar surface, allowing us to constrain stellar rotation and magnetic activity. In this work we investigate the…

Recent years have seen an increased interest in the question of whether the gravitational action of planets could have an influence on the solar dynamo. Without discussing the observational validity of the claimed correlations, we ask for a…

Solar and Stellar Astrophysics · Physics 2016-09-21 F. Stefani , A. Giesecke , N. Weber , T. Weier

This work investigates the solar quasi-periodic cycles with multi-timescales and the possible relationships with planetary motions. The solar cycles are derived from long-term observations of the relative sunspot number and microwave…

Solar and Stellar Astrophysics · Physics 2012-10-16 Baolin Tan , Zhuo Cheng

The 3D structure of solar wind and its evolution in time is needed for heliospheric modeling and interpretation of energetic neutral atoms observations. We present a model to retrieve the solar wind structure in heliolatitude and time using…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. M. Sokol , M. Bzowski , M. Tokumaru , K. Fujiki , D. J. McComas

This work is a continuation of our previous articles (Yermolaev et al. in J. Geophys.Res. 120, 7094, 2015, Yermolaev et al. in Solar Phys. 292, 193, 2017), which describe the average temporal profiles of interplanetary plasma and field…

Space Physics · Physics 2018-07-11 Yu. I. Yermolaev , I. G. Lodkina , M. Yu. Yermolaev

We have determined the solar modulation potential, phi, vs. time that is observed at Voyager 1 and 2 from measurements of the H and He nuclei intensities at a common energy of 250 MeVnuc. The H nuclei have a rigidity 0.7 GV, the He nuclei…

Space Physics · Physics 2017-06-12 W. R. Webber , E. C. Stone , A. C. Cummings , B. Heikkila , N. Lal

The solar wind provides a natural laboratory for observations of MHD turbulence over extended temporal scales. Here, we apply a model independent method of differencing and rescaling to identify self-similarity in the Probability Density…

Space Physics · Physics 2009-11-07 Bogdan Hnat , Sandra C. Chapman , George Rowlands

The solar interior is probed by the properties of the Sun's acoustic oscillations (p-modes) observed on the solar surface. The frequencies of these p-modes measured in the last three decades show long term variation similar to the 11 year…

Solar and Stellar Astrophysics · Physics 2026-04-23 Rekha Jain , Akash Kumar , Sushanta C. Tripathy

Fluctuations in the flow velocity and magnetic fields are ubiquitous in the Solar System. These fluctuations are turbulent, in the sense that they are disordered and span a broad range of scales in both space and time. The study of solar…

Solar and Stellar Astrophysics · Physics 2016-02-04 F. Fraternale , L. Gallana , M. Iovieno , M. Opher , J. D. Richardson , D. Tordella

Precise, high-cadence, long-term records of stellar spectral variability at different temporal scales lead to better understanding of a wide variety of phenomena including stellar atmospheres and dynamos, convective motions, and rotational…

Solar and Stellar Astrophysics · Physics 2023-07-19 Serena Criscuoli , Sergey Marchenko , Matthew DeLand , Debi Choudhary , Greg Kopp

Hydrodynamic jets are unstable to the kink instability (m=1 mode in cylindrical geometry) owing to the centripetal force, which increases the transverse displacement of the jet. When the jet moves along a magnetic field, then the Lorentz…

Solar and Stellar Astrophysics · Physics 2020-05-06 T. V. Zaqarashvili

We present a study of the solar wind over different periods of the solar cycle, specifically focussing on the minimum between solar cycles 24 and 25, and the active, ascending phase of solar cycle 25. With the use of interplanetary…

Solar and Stellar Astrophysics · Physics 2025-06-18 A. Waszewski , J. S. Morgan , R. Ekers , M. Johnston-Hollitt , M. C. M. Cheung , N. D. R. Bhat , R. Chhetri , S. C. Fu

We present evidence that the sound-speed variation with solar activity has a two-layer configuration, similar to the one observed below an active region, which consists of a negative layer near the solar surface and a positive one in the…

Solar and Stellar Astrophysics · Physics 2015-05-30 M. Cristina Rabello-Soares

Commenting the 11-year sunspot cycle, Wolf (1859, MNRAS 19, 85-86) conjectured that "the variations of spot frequency depend on the influences of Venus, Earth, Jupiter, and Saturn". The high synchronization of our planetary system is…

Geophysics · Physics 2022-08-22 Nicola Scafetta , Antonio Bianchini

Spectroscopic equilibrium allows us to obtain precise stellar parameters in Sun-like stars. It relies on the assumption of the iron excitation and ionization equilibrium. However, several works suggest that magnetic activity may affect…

In this work, we studied the characteristics and dynamical changes during the recovery time of moderate and strong geomagnetic storms (Dst $<-50$ nT). Investigating 57 storms triggered by CMEs/CIRs, we focused on the solar wind's influence…

Space Physics · Physics 2024-07-03 O. Ahmed , B. Badruddin , M. Derouich

We analyze the effect of solar features on the variability of the solar irradiance in three different spectral ranges. Our study is based on two solar-cycles' worth of full-disk photometric images from the San Fernando Observatory, obtained…

Solar and Stellar Astrophysics · Physics 2015-05-28 Dora Preminger , Gary Chapman , Angela Cookson

Herein we adopt a multi-scale dynamical spectral analysis technique to compare and study the dynamical evolution of the harmonic components of the overlapping ACRIMSAT/ACRIM3, SOHO/VIRGO and SORCE/TIM total solar irradiance (TSI) records…

General Physics · Physics 2013-11-28 Nicola Scafetta , Richard C. Willson