English
Related papers

Related papers: Constraining solar wind transport model parameters…

200 papers

A methodology is developed, based on nonparametric Bayesian dictionary learning, for joint space-time wind field data extrapolation and estimation of related statistics by relying on limited/incomplete measurements. Specifically, utilizing…

Machine Learning · Statistics 2025-07-16 George D. Pasparakis , Ioannis A. Kougioumtzoglou , Michael D. Shields

High resolution observations have permitted to resolve the solar prominences/filaments as sets of threads/fibrils. However, the values of the physical parameters of these threads and their structuring remain poorly constrained. We use…

Solar and Stellar Astrophysics · Physics 2019-02-06 M. Montes-Solís , I. Arregui

The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor…

Solar and Stellar Astrophysics · Physics 2015-06-19 G. G. Howes , K. G. Klein , J. M. TenBarge

By means of self-consistent 3D MHD numerical simulations, we analyze magnetized solar-like stellar winds and their dependence on the plasma-beta parameter. We adopt in our simulations a heating parameter described by gamma, which is…

Solar and Stellar Astrophysics · Physics 2011-02-11 A. A. Vidotto , M. Opher , V. Jatenco-Pereira , T. I. Gombosi

A key prediction of turbulence theories is frame-invariance, and in magnetohydrodynamic (MHD) turbulence, axisymmetry of fluctuations with respect to the background magnetic field. Paradoxically the power in fluctuations in the turbulent…

Solar and Stellar Astrophysics · Physics 2011-10-14 A. J. Turner , G. Gogoberidze , S. C. Chapman , B. Hnat , W. -C. Mueller

In this article, we study the well known problem of wind estimation in atmospheric turbulence using small unmanned aerial systems (sUAS). We present a machine learning approach to wind velocity estimation based on quadcopter state…

Signal Processing · Electrical Eng. & Systems 2019-07-15 Sam Allison , He Bai , Balaji Jayaraman

Understanding the mechanism(s) of the solar wind acceleration is important in astrophysics and geophysics. A promising model of the solar wind acceleration is known as the wave/turbulence-driven (WTD) model, in which Alfv\'en waves feed…

Solar and Stellar Astrophysics · Physics 2022-04-13 Munehito Shoda , Kazumasa Iwai , Daikou Shiota

Turbulence is a dominant feature operating in gaseous flows across nearly all scales in astrophysical environments. Accordingly, accurately estimating the statistical properties of such flows is necessary for developing a comprehensive…

Solar and Stellar Astrophysics · Physics 2014-11-27 Lukas Konstandin , Rahul Shetty , Philipp Girichidis , Ralf S. Klessen

Tracer-kinetic analysis of dynamic contrast-enhanced magnetic resonance imaging data is commonly performed with the well-known Tofts model and nonlinear least squares (NLLS) regression. This approach yields point estimates of model…

Medical Physics · Physics 2020-01-08 Andreas Mittermeier , Birgit Ertl-Wagner , Jens Ricke , Olaf Dietrich , Michael Ingrisch

We study the transport of high-energy particles in pulsar wind nebulae (PWN) using three-dimensional MHD (see Porth et al. (2014) for details) and test-particle simulations, as well as a Fokker-Planck particle transport model. The latter…

High Energy Astrophysical Phenomena · Physics 2016-07-27 O. Porth , M. J. Vorster , M. Lyutikov , N. E. Engelbrecht

We study the evolution of turbulence in the solar wind by solving numerically the full 3D magneto-hydrodynamic (MHD) equations embedded in a radial mean wind. The corresponding equations (expanding box model or EBM) have been considered…

Solar and Stellar Astrophysics · Physics 2015-06-22 Yue Dong , Andrea Verdini , Roland Grappin

We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the…

Space Physics · Physics 2020-09-01 L. Matteini , L. Franci , O. Alexandrova , C. Lacombe , S. Landi , P. Hellinger , E. Papini , A. Verdini

The Solar Orbiter (SO) mission provides the opportunity to study the evolution of solar wind turbulence. We use SO observations of nine extended intervals of homogeneous turbulence to determine when turbulent magnetic field fluctuations may…

Solar and Stellar Astrophysics · Physics 2024-06-17 Alina Bendt , Sandra C. Chapman , Thierry Dudok de Wit

Context. The Sun is a privileged laboratory of stellar evolution, thanks to the quality and complementary nature of available constraints. Using these observations, we are able to draw a detailed picture of its internal structure and…

Solar and Stellar Astrophysics · Physics 2025-02-26 G. Buldgen , A. Noels , A. M. Amarsi , D. Nandal , C. Pezzotti , R. Scuflaire , M. Deal , N. Grevesse

We present the implementation of turbulence transport equations in addition to the Reynolds-averaged MHD equations within the Cronos framework. The model is validated by comparisons with earlier findings before it is extended to be…

Solar and Stellar Astrophysics · Physics 2015-06-03 Tobias Wiengarten , Horst Fichtner , Jens Kleimann , Ralf Kissmann

Turbulence is a ubiquitous process that transfers energy across many spatial and temporal scales, thereby influencing particle transport and heating. Recent progress has improved our understanding of the anisotropy of turbulence with…

Solar and Stellar Astrophysics · Physics 2025-12-08 Siqi Zhao , Huirong Yan , Terry Z. Liu , Chuanpeng Hou

Recent success in explaining several properties of the dusty torus around the central engine of active galactic nuclei has been gathered with the assumption of clumpiness. The properties of such clumpy dusty tori can be inferred by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 A. Asensio Ramos , C. Ramos Almeida

We present an approach to turbulence closure based on mixing length theory with three-dimensional fluctuations against a two-dimensional background. This model is intended to be rapidly computable for implementation in stellar evolution…

Solar and Stellar Astrophysics · Physics 2018-09-28 Adam S. Jermyn , Pierre Lesaffre , Christopher A. Tout , Shashikumar M. Chitre

We apply statistical analysis to search for processes responsible for turbulence in physical systems. In our previous studies, we have shown that solar wind turbulence in the inertial range of large magnetohydrodynamic scales exhibits…

Plasma Physics · Physics 2025-03-13 Dariusz Wójcik , Wiesław M. Macek

Accurate subgrid-scale turbulence models are needed to perform realistic numerical magnetohydrodynamic (MHD) simulations of the subsurface flows of the Sun. To perform large-eddy simulations (LES) of turbulent MHD flows, three unknown terms…

Solar and Stellar Astrophysics · Physics 2010-10-28 G. Balarac , A. G. Kosovichev , O. Brugière , A. A. Wray , N. N. Mansour