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Related papers: A new MHD-assisted Stokes inversion technique

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Penalised estimation methods for point processes usually rely on a large amount of independent repetitions for cross-validation purposes. However, in the case of a single realisation of the process, existing cross-validation methods may be…

Methodology · Statistics 2026-01-13 Miguel Martinez Herrera , Felix Cheysson

Multivariate Hawkes Processes (MHPs) are an important class of temporal point processes that have enabled key advances in understanding and predicting social information systems. However, due to their complex modeling of temporal…

Machine Learning · Computer Science 2020-03-02 Maximilian Nickel , Matthew Le

We present an approach to spectropolarimetry which requires neither moving parts nor time dependent modulation, and which offers the prospect of achieving high sensitivity. The technique applies equally well, in principle, in the optical,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 William Sparks , Thomas A. Germer , John MacKenty , Frans Snik

We investigate the convergence of stochastic mirror descent (SMD) under interpolation in relatively smooth and smooth convex optimization. In relatively smooth convex optimization we provide new convergence guarantees for SMD with a…

Optimization and Control · Mathematics 2023-05-26 Ryan D'Orazio , Nicolas Loizou , Issam Laradji , Ioannis Mitliagkas

Solar wind conditions are predominantly predicted via three-dimensional numerical magnetohydrodynamic (MHD) models. Despite their ability to produce highly accurate predictions, MHD models require computationally intensive high-dimensional…

Computational Physics · Physics 2022-11-30 Opal Issan , Boris Kramer

For the Stokes equation over 2D and 3D domains, explicit a posteriori and a priori error estimation are novelly developed for the finite element solution. The difficulty in handling the divergence-free condition of the Stokes equation is…

Numerical Analysis · Mathematics 2020-06-05 Xuefeng Liu , Mitsuhiro Nakao , Chun'guang You , Shin'ichi Oishi

Magnetohydrodynamic (MHD) seismology uses naturally occurring MHD waves to infer plasma properties that are otherwise hard to measure, especially magnetic field strength and topology, electric currents, fine structuring, transport…

Estimating subsurface properties like hydraulic conductivity using hydrogeological data alone is challenging in field sites with sparse wells. Geophysical data, including Self-potential (SP) and Magnetotelluric (MT), can improve…

Geophysics · Physics 2025-01-20 Young-Ho Seo , Jonghyun Lee , Aly I. El-Kadi , Niels Grobbe

We present a new iterative rotation inversion technique based on the Simultaneous Algebraic Reconstruction Technique developed for image reconstruction. We describe in detail our algorithmic implementation and compare it to the classical…

Solar and Stellar Astrophysics · Physics 2024-06-17 Sylvain G. Korzennik , Antonio Eff-Darwich

The standard smooth electrical resistivity tomography inversion produces an estimate of subsurface conductivity that has blurred boundaries, damped magnitudes, and often contains inversion artifacts. In many problems the expected…

Geophysics · Physics 2021-12-08 Teddi Herring , Lindsey J. Heagy , Adam Pidlisecky , Edwin Cey

Solar pores are active regions with large magnetic field strengths and apparent simple magnetic configurations. Their properties resemble the ones found for the sunspot umbra although pores do not show penumbra. Therefore, solar pores…

Solar and Stellar Astrophysics · Physics 2016-06-15 C. Quintero Noda , T. Shimizu , B. Ruiz Cobo , Y. Suematsu , Y. Katsukawa , K. Ichimoto

Accurate soil moisture (SM) estimation is critical for precision agriculture, water resources management and climate monitoring. Yet, existing satellite SM products are too coarse (>1km) for farm-level applications. We present a…

Computer Vision and Pattern Recognition · Computer Science 2026-02-23 Ioannis Kontogiorgakis , Athanasios Askitopoulos , Iason Tsardanidis , Dimitrios Bormpoudakis , Ilias Tsoumas , Fotios Balampanis , Charalampos Kontoes

Three-dimensional (3D) radiative magnetohydrodynamics (MHD) simulations are the only way to model stellar atmospheres without any ad hoc parameterisations. Several 3D radiative MHD codes have achieved good quantitative agreement with…

Extended MHD is a one-fluid model that incorporates two-fluid effects such as electron inertia and the Hall drift. This model is used to construct fully nonlinear Alfv\'enic wave solutions, and thereby derive the kinetic and magnetic…

Plasma Physics · Physics 2016-10-05 Hamdi M. Abdelhamid , Manasvi Lingam , Swadesh M. Mahajan

Stokes polarimetry is widely used to extract the polarisation structure of optical fields, typically from six measurements, although it can be extracted from only four. To measure the required intensities, most approaches are based on…

The global demand for unconventional energy sources such as geothermal energy and white hydrogen requires new exploration techniques for precise subsurface structure characterization and potential reservoir identification. The…

Geophysics · Physics 2025-01-15 Paul Goyes-Peñafiel , Umair bin Waheed , Henry Arguello

In this paper we describe in detail the implementation and main properties of a new inversion code for the polarized radiative transfer equation (VFISV: Very Fast inversion of the Stokes vector). VFISV will routinely analyze pipeline data…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 J. M. Borrero , S. Tomczyk , M. Kubo , H. Socas-Navarro , J. Schou , S. Couvidat , R. Bogart

Changes in the solar surface area covered by small-scale magnetic elements are thought to cause long-term changes in the solar spectral irradiance, which are important for determining the impact on Earth's climate. To study the effect of…

Solar and Stellar Astrophysics · Physics 2015-05-20 N. Afram , Y. C. Unruh , S. K. Solanki , M. Schuessler , A. Lagg , A. Voegler

Spectral clustering is a fundamental technique in the field of data mining and information processing. Most existing spectral clustering algorithms integrate dimensionality reduction into the clustering process assisted by manifold learning…

Machine Learning · Computer Science 2014-11-25 Xiaojun Chang , Feiping Nie , Zhigang Ma , Yi Yang , Xiaofang Zhou

We present a technique to construct a spectropolarimetrically accurate magneto-hydrostatic model of a large-scale solar magnetic field concentration, mimicking a sunspot. Using the constructed model we perform a simulation of acoustic wave…

Solar and Stellar Astrophysics · Physics 2015-04-10 D. Przybylski , S. Shelyag , P. S. Cally
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