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Related papers: Modeling Solar Wind Variations over an 11-yr Cycle…

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The origin of the heliospheric magnetic flux on the Sun, and hence the origin of the solar wind, is a topic of hot debate.While the prevailing view is that the solar wind originates from outside coronal streamer helmets, there also exists…

Solar and Stellar Astrophysics · Physics 2015-06-05 Bo Li , Xing Li , Hui Yu

The mixture/interaction of anti-sunward-propagating Alfv\'enic fluctuations (AFs) and sunward-propagating Alfv\'enic fluctuations (SAFs) is believed to result in the decrease of the Alfv\'enicity of solar wind fluctuations with increasing…

Space Physics · Physics 2016-06-13 H. Li , C. Wang , J. W. Belcher , J. S. He , J. D. Richardson

The physical processes that heat the solar corona and accelerate the solar wind remain unknown after many years of study. Some have suggested that the wind is driven by waves and turbulence in open magnetic flux tubes, and others have…

Solar and Stellar Astrophysics · Physics 2015-05-19 Steven R. Cranmer , Adriaan A. van Ballegooijen

Alfven waves have been invoked as an important mechanism of particle acceleration in stellar winds of cool stars. After their identification in the solar wind they started to be studied in winds of stars located in different regions of the…

Solar and Stellar Astrophysics · Physics 2014-11-18 A. A. Vidotto , V. Jatenco-Pereira

The solar wind is connected to the Sun's atmosphere by flux tubes that are rooted in an ever-changing pattern of positive and negative magnetic polarities on the surface. Observations indicate that the magnetic field is filamentary and…

Solar and Stellar Astrophysics · Physics 2015-06-15 Steven R. Cranmer , Adriaan A. van Ballegooijen , Lauren N. Woolsey

In the present paper, the proton velocity distribution function (VDF)in the solar wind is determined by solving numerically the kinetic evolution equation. We compare the results obtained when considering the effects of ex- ternal forces…

Space Physics · Physics 2013-05-22 Viviane Pierrard , Yuriy Voitenko

Many cool stars possess complex magnetic fields [1] that are considered to undertake a central role in the structuring and energising of their atmospheres [2]. Alfv\'enic waves are thought to make a critical contribution to energy transfer…

Solar and Stellar Astrophysics · Physics 2019-02-12 R. J. Morton , M. Weberg , J. A. McLaughlin

We perform a validation study of the latest version of the Alfv\'{e}n Wave Solar atmosphere Model (AWSoM) within the Space Weather Modeling Framework (SWMF). To do so, we compare the simulation results of the model with a comprehensive…

In this letter, we investigate the population of energetically-dominant sunward-propagating Alfv\'en waves (SAWs) using more than 20 years of data provided by the Wind spacecraft near 1 au. We refer to SAWs as energetically-dominant…

Space Physics · Physics 2025-12-23 Nickolas Giardetti , Sofiane Bourouaine , Jean C. Perez

Cool giant and supergiant stars generally present low velocity winds with high mass loss rates. Several models have been proposed to explain the acceleration process of these winds. Although dust is known to be present in these objects, the…

Astrophysics · Physics 2009-11-11 A. A. Vidotto , D. Falceta-Goncalves , V. Jatenco-Pereira

Solar wind streams, acting as background, govern the propagation of space weather drivers in the heliosphere, which induce geomagnetic storm activities. Therefore, predictions of the solar wind parameters are the core of space weather…

Solar and Stellar Astrophysics · Physics 2022-09-14 Prateek Mayank , Bhargav Vaidya , D. Chakrabarty

By using our previous results of magnetohydrodynamical simulations for the solar wind from open flux tubes, I discuss how the solar wind in the past is different from the current solar wind. The simulations are performed in fixed…

Solar and Stellar Astrophysics · Physics 2015-05-27 Takeru K. Suzuki

We use magnetic helicity to characterise solar wind fluctuations at proton-kinetic scales from Wind observations. For the first time, we separate the contributions to helicity from fluctuations propagating at angles quasi-parallel and…

During the last decades, international attempts have been made to develop realistic space weather prediction tools aiming to forecast the conditions on the Sun and in the interplanetary environment. These efforts have led to the development…

We use fluctuating magnetic helicity to investigate the polarisation properties of Alfv\'enic fluctuations at ion-kinetic scales in the solar wind as a function of $\beta_p$, the ratio of proton thermal pressure to magnetic pressure, and…

Space Physics · Physics 2022-04-12 L. D. Woodham , R. T. Wicks , D. Verscharen , J. M. TenBarge , G. G. Howes

Alfv\'en waves are primal and pervasive in space plasmas and significantly contributes to microscale fluctuations in the solar wind and some heliospheric processes. Here, we demonstrate the first observable distinct feature of Alfv\'en wave…

Space Physics · Physics 2018-10-16 Anil N. Raghav , Ankita Kule

Forecasting models of the solar wind often rely on simple parameterizations of the magnetic field that ignore the effects of the full magnetic field geometry. In this paper, we present the results of two solar wind prediction models that…

Solar and Stellar Astrophysics · Physics 2015-06-19 Lauren N. Woolsey , Steven R. Cranmer

The collisionless dissipation of anisotropic Alfv\'enic turbulence is a promising candidate to solve the solar wind heating problem. Extensive studies examined the kinetic properties of Alfv\'en waves in simple Maxwellian or bi-Maxwellian…

Solar and Stellar Astrophysics · Physics 2015-05-12 Yuguang Tong , Stuart D. Bale , Christopher H. K. Chen , Chadi S. Salem , Daniel Verscharen

In the present paper we study impact of the photospheric 5-minute oscillations on the ion cyclotron waves in the solar wind. We proceed from the assumption that the ion cyclotron waves in solar wind are experiencing modulation with a…

Space Physics · Physics 2015-10-28 Anatol Guglielmi , Alexander Potapov , Boris Dovbnya

Motivated by theoretical, numerical, and observational evidence, we explore the possibility that the critical transition between sub-Alfv\'enic flow and super-Alfv\'enic flow in the solar atmosphere takes place in fragmented and…

Solar and Stellar Astrophysics · Physics 2022-11-23 Rohit Chhiber , William H. Matthaeus , Arcadi V. Usmanov , Riddhi Bandyopadhyay , Melvyn L. Goldstein