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The standing quasi modes in a cylindrical incompressible flux tube with magnetic twist that undergoes a radial density structuring is considered in ideal magnetohydrodynamics (MHD). The radial structuring is assumed to be a linearly varying…

Solar and Stellar Astrophysics · Physics 2011-05-06 K. Karami , K. Bahari

Proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) are two complementary singular-value decomposition (SVD) techniques that are widely used to construct reduced-order models (ROMs) in a variety of fields of science…

Numerical Analysis · Mathematics 2020-02-19 Hannah Lu , Daniel M. Tartakovsky

It is now well accepted that the detection of impulsively generated multiple MHD modes are potentially used in diagnosing the local plasma conditions of the solar corona. Analogously, such analyses can also be significantly used in…

Solar and Stellar Astrophysics · Physics 2014-01-24 A. K. Srivastava , S. Lalitha

In this paper, we combine concepts of the generalized multiscale finite element method and mode decomposition methods to construct a robust local-global approach for model reduction of flows in high-contrast porous media. This is achieved…

Computational Physics · Physics 2013-01-25 Mehdi Ghommem , Michael Presho , Victor M. Calo , Yalchin Efendiev

The high spatial, temporal and spectral resolution achieved by Hinode instruments give much better understanding of the behavior of some elusive solar features, such as pores and naked sunspots. Their fast evolution and, in some cases,…

Solar and Stellar Astrophysics · Physics 2012-02-06 A. Sainz Dalda , S. Vargas Dominguez , T. D. Tarbell

Magnetoseismology, a technique of magnetic field diagnostics based on observations of magnetohydrodynamic (MHD) waves, has been widely used to estimate the field strengths of oscillating structures in the solar corona. However, previously…

Solar and Stellar Astrophysics · Physics 2020-11-05 Zihao Yang , Hui Tian , Steven Tomczyk , Richard Morton , Xianyong Bai , Tanmoy Samanta , Yajie Chen

A specific type of artifacts, that originate due to displacement of the image of a moving object along the digital (pixel) matrix of receiver are analyzed in detail. The criteria of appearance and the influence of these artifacts on the…

Solar and Stellar Astrophysics · Physics 2018-03-21 V. I. Efremov , A. A. Soloviev , L. D. Parfinenko , A. Riehokainen , E. Kirichek , V. V. Smirnova , Y. N. Varun , I. Bakunina , I. Zhivanovich

Mode division multiplexing (MDM) systems leveraging spatial modes carrying orbital angular momentum (OAM) present a promising approach to enhance communication capacity in free-space and fiber-optic networks. Efficient detection of OAM…

Optics · Physics 2025-02-27 Amin Hakimi , S. Faezeh Mousavi , Amir Nader Askarpour

The continuous high spatial-resolution Doppler observation of the Sun by Solar Dynamics Observatory / Helioseismic and Magnetic Imager allows us to compute helioseismic k-omega power-spectrum diagram using only oscillations inside a…

Solar and Stellar Astrophysics · Physics 2015-06-11 Junwei Zhao , Dean-Yi Chou

We present a new method that combines the results of an oscillation study made in optical and radio observations. The optical spectral measurements in photospheric and chromospheric lines of the line-of-sight velocity were carried out at…

Solar and Stellar Astrophysics · Physics 2015-03-18 V. E. Abramov-Maximov , G. B. Gelfreikh , N. I. Kobanov , K. Shibasaki , S. A. Chupin

Investigation of propagation, conversion, and scattering of MHD waves in the Sun is very important for understanding the mechanisms of observed oscillations and waves in sunspots and active regions. We have developed 3D linear MHD numerical…

Astrophysics · Physics 2011-02-11 K. V. Parchevsky , A. G. Kosovichev

Vector magnetic fields of moving magnetic features (MMFs) are well observed with the Solar Optical Telescope (SOT) aboard the Hinode satellite. We focus on the evolution of three MMFs with the SOT in this study. We found that an MMF having…

In the applications of solar magneto-seismology(SMS), employing the ratio of the period of the fundamental mode to twice the one of its first overtone, $P_1/2P_2$, plays an important role. We examine how field-aligned flows affect the…

Solar and Stellar Astrophysics · Physics 2015-06-15 Bo Li , Shadia Rifai Habbal , Yanjun Chen

This article reviews some of the leading results obtained in solar dynamo physics by using temporal oscillator models as a tool to interpret observational data and dynamo model predictions. We discuss how solar observational data such as…

Solar and Stellar Astrophysics · Physics 2014-07-21 Ilídio Lopes , Dário Passos , Melinda Nagy , Kristof Petrovay

While the acquisition of time series has become more straightforward, developing dynamical models from time series is still a challenging and evolving problem domain. Within the last several years, to address this problem, there has been a…

Machine Learning · Computer Science 2023-07-19 Christopher W. Curtis , D. Jay Alford-Lago , Erik Bollt , Andrew Tuma

We present a new method for generating robust guesses for unstable periodic orbits (UPOs) by post-processing turbulent data using dynamic mode decomposition (DMD). The approach relies on the identification of near-neutral, repeated…

Fluid Dynamics · Physics 2020-02-19 Jacob Page , Rich R. Kerswell

Structural health monitoring (SHM) is an essential engineering field aimed at ensuring the safety and reliability of civil infrastructures. This study proposes a methodology using multivariate variational mode decomposition (MVMD) for…

Applications · Statistics 2025-04-16 Lakhadive Mehulkumar R , Anshu Sharma , Basuraj Bhowmik

This paper explores the effects of numerical algorithms on global magnetohydrodynamics (MHD) simulations of solar wind (SW) in the inner heliosphere. To do so, we use sunRunner3D, a 3-D MHD model that employs the boundary conditions…

Solar and Stellar Astrophysics · Physics 2024-05-03 Luis Ángel de León Alanís , J. J. González-Avilés , P. Riley , M. Ben-Nun

We present a 106-minute TiO (705.7nm) time series of high spatial and temporal resolution that contains thousands of umbral dots (UDs) in a mature sunspot in the active region NOAA 10667 at $\mu$=0.95. The data were acquired with the 1-m…

Astrophysics · Physics 2008-12-03 T. L. Riethmueller , S. K. Solanki , V. Zakharov , A. Gandorfer

We present for astrophysical use a multi-dimensional numerical code to solve the equations for ideal magnetohydrodynamics (MHD). It is based on an explicit finite difference method on an Eulerian grid, called the Total Variation Diminishing…

Astrophysics · Physics 2016-08-30 Dongsu Ryu , T. W. Jones , Adam Frank
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