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We present a method for performing data-driven simulations of solar active region formation and evolution. The approach is based on magnetofriction, which evolves the induction equation assuming the plasma velocity is proportional to the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Mark C. M. Cheung , Marc L. DeRosa

Data assimilation (DA) is a fundamental computational technique that integrates numerical simulation models and observation data on the basis of Bayesian statistics. Originally developed for meteorology, especially weather forecasting, DA…

SDO-FM is a foundation model using data from NASA's Solar Dynamics Observatory (SDO) spacecraft; integrating three separate instruments to encapsulate the Sun's complex physical interactions into a multi-modal embedding space. This model…

We discuss a prediction of the solar activity on a short time-scale applying the method based on a combination of a nonlinear mean-field dynamo model and the artificial neural network. The artificial neural network which serves as a…

We introduce on/off intermittency into a mean field dynamo model by imposing stochastic fluctuations in either the alpha effect or through the inclusion of a fluctuating electromotive force. Sufficiently strong small scale fluctuations with…

Astrophysics · Physics 2008-03-27 A. Brandenburg , E. A. Spiegel

Solar modelling has long been split into ''internal'' and ''surface'' modelling, because of the lack of tools to connect the very different scales in space and time, as well as the widely different environments and dominating physical…

Solar and Stellar Astrophysics · Physics 2022-11-18 Andrius Popovas , Åke Nordlund , Mikolaj Szydlarski

A framework for data assimilation combining aspects of operator-theoretic ergodic theory and quantum mechanics is developed. This framework adapts the Dirac--von Neumann formalism of quantum dynamics and measurement to perform sequential…

Mathematical Physics · Physics 2019-09-18 Dimitrios Giannakis

In this article we develop algorithms for data assimilation based upon a computational time dependent stable/unstable splitting. Our particular method is based upon shadowing refinement and synchronization techniques and is motivated by…

Dynamical Systems · Mathematics 2017-07-31 Bart de Leeuw , Svetlana Dubinkina , Jason Frank , Andrew Steyer , Xuemin Tu , Erik Van Vleck

We consider a conventional $\alpha-\Omega$-dynamo model with meridional circulation that exhibits typical features of the solar dynamo, including a Hale cycle period of around 20 years and a reasonable shape of the butterfly diagram. With…

Solar and Stellar Astrophysics · Physics 2023-07-26 M. Klevs , F. Stefani , L. Jouve

We show existence of strong negative correlation between the temporal variations of magnetic field toroidal component of the solar tachocline (the bottom of convective zone) and the Earth magnetic field (Y-component). The possibility that…

Earth and Planetary Astrophysics · Physics 2010-08-17 V. D. Rusov , E. P. Linnik , K. Kudela , S. Cht. Mavrodiev , T. N. Zelentsova , V. P. Smolyar , K. K. Merkotan

In this article we develop further an algorithm for data assimilation based upon a shadowing refinement technique [de Leeuw et al., SIAM J. Appl. Dyn. Sys., 17 (2018)] to take partial observations into account. Our method is based on…

Optimization and Control · Mathematics 2020-11-13 Bart de Leeuw , Svetlana Dubinkina

The solar atmosphere being magnetic in nature, the understanding of the structure and evolution of the magnetic field in different regions of the solar atmosphere has been an important task over the past decades. This task has been made…

Solar and Stellar Astrophysics · Physics 2015-06-16 S. Regnier

In applications such as free-space optical communication, a signal is often recovered after propagation through a turbulent medium. In this setting, it is common to assume that limited information is known about the turbulent medium, such…

Optics · Physics 2025-10-13 Anjali Nair , Qin Li , Samuel N. Stechmann

Data assimilation plays a crucial role in modern weather prediction, providing a systematic way to incorporate observational data into complex dynamical models. The paper addresses continuous data assimilation for a model arising as a…

Analysis of PDEs · Mathematics 2026-02-03 Eduard Feireisl , Piotr Gwiazda , Agnieszka Świerczewska-Gwiazda

In recent years, the convergence of data-driven machine learning models with Data Assimilation (DA) offers a promising avenue for enhancing weather forecasting. This study delves into this emerging trend, presenting our methodologies and…

Atmospheric and Oceanic Physics · Physics 2024-01-17 Wenqi Wang , Jacob Bieker , Rossella Arcucci , César Quilodrán-Casas

A magnetic flux tube may be considered both as a separate body and as a confined field. As a field, it is affected both by the cyclonic convection ($\alpha$-effect) and differential rotation ($\Omega$-effect). As a body, the tube…

Astrophysics · Physics 2007-05-23 L. H. Li , S. Sofia

We explore consequences for the solar dynamo of a newly-developed physical hypothesis describing a weak coupling of the orbital and rotational motions of extended bodies. The coupling is given by - c ((dL/dt) x omega sub alpha) x r, where…

Solar and Stellar Astrophysics · Physics 2017-06-07 James H. Shirley

The need for reliable predictions of the solar activity cycle motivates the development of dynamo models incorporating a representation of surface processes sufficiently detailed to allow assimilation of magnetographic data. In this series…

Solar and Stellar Astrophysics · Physics 2015-11-30 Alexandre Lemerle , Paul Charbonneau , Arnaud Carignan-Dugas

In this work we use a low order dynamo model and study under which conditions can it reproduce solar grand minima. We begin by building the phase space of a proxy for the toroidal component of the solar magnetic field and we develop a…

Solar and Stellar Astrophysics · Physics 2015-02-05 Dario Passos , Ilidio P. Lopes

Space-weather and disturbances in the heliosphere are manifestations of the solar magnetic field, which is solely driven by the interior dynamo, and constraining the solar interior magnetic field and its oscillatory behavior is one of the…

Solar and Stellar Astrophysics · Physics 2025-12-29 Soumyadeep Chatterjee , Gopal Hazra
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