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The plasma parameters such as the electron density and temperature plays a key role in the dynamics of the solar atmosphere. These characteristics are important in solar physics, because they can help to understand the physics in the solar…

Solar and Stellar Astrophysics · Physics 2018-04-12 J. M Rodríguez Gómez , L. Vieira , A. Dal Lago , J. Palacios

Practical applications of thermoacoustic tomography require numerical inversion of the spherical mean Radon transform with the centers of integration spheres occupying an open surface. Solution of this problem is needed (both in 2-D and…

Analysis of PDEs · Mathematics 2009-11-13 Leonid Kunyansky

We develop and apply an enhanced regularization algorithm, used in RHESSI X-ray spectral analysis, to constrain the ill-posed inverse problem that is determining the DEM from solar observations. We demonstrate this computationally fast…

Solar and Stellar Astrophysics · Physics 2015-06-03 I. G. Hannah , E. P. Kontar

Recent progress in obtaining high spatial resolution images of the solar corona in the extreme-ultraviolet (EUV) with Hinode, TRACE, SDO and recent Hi-C missions and soft X-ray (SXR) bands opened a new avenue in understanding the solar…

Solar and Stellar Astrophysics · Physics 2014-09-16 V. S. Airapetian , J. Allred

We compare the ability of 11 Differential Emission Measure (DEM) forward-fitting and inversion methods to constrain the properties of active regions and solar flares by simulating synthetic data using the instrumental response functions of…

Solar and Stellar Astrophysics · Physics 2016-04-13 M. J. Aschwanden , P. Boerner , A. Caspi , J. M. McTiernan , D. Ryan , H. P. Warren

The paper surveys recent progress in establishing uniqueness and developing inversion formulas and algorithms for the thermoacoustic tomography. In mathematical terms, one deals with a rather special inverse problem for the wave equation.…

Analysis of PDEs · Mathematics 2009-02-02 M. Agranovsky , P. Kuchment , L. Kunyansky

We undertake a first attempt towards a consistent reconstruction of the coronal magnetic field and the coronal density structure. We consider a stationary solar corona which has to obey the equations of magnetohydrostatics. We solve these…

Astrophysics · Physics 2009-06-25 T. Wiegelmann , B. Inhester

A simple, yet powerful, algorithm for computed tomography of the solar corona is presented and demonstrated using synthetic EUV data. A minimum of three perspectives are required. These may be obtained from STEREO/EUVI plus an instrument…

Astrophysics · Physics 2008-07-15 Charles C. Kankelborg

In this paper, we address the inverse problem of fast, stable, and high-quality wavefront reconstruction from pyramid wavefront sensor data for Adaptive Optics systems on Extremely Large Telescopes. For solving the indicated problem we…

Instrumentation and Methods for Astrophysics · Physics 2019-05-01 Victoria Hutterer , Ronny Ramlau , Iuliia Shatokhina

We introduce the EMC algorithm for reconstructing a particle's 3D diffraction intensity from very many photon shot-noise limited 2D measurements, when the particle orientation in each measurement is unknown. The algorithm combines a…

Data Analysis, Statistics and Probability · Physics 2010-03-04 Duane Ne-Te Loh , Veit Elser

In this paper, we study the temperature and density properties of multiple structural components of coronal mass ejections (CMEs) using differential emission measure (DEM) analysis. The DEM analysis is based on the six-passband EUV…

Solar and Stellar Astrophysics · Physics 2015-06-11 X. Cheng , J. Zhang , S. H. Saar , M. D. Ding

We present a novel method for reconstructing the thermal conductivity coefficient in 1D and 2D heat equations using moving sensors that dynamically traverse the domain to record sparse and noisy temperature measurements. We significantly…

Numerical Analysis · Mathematics 2024-10-31 Guangting Yu , Shiwei Lan , Kookjin Lee , Alex Mahalov

The structure of the solar corona is made of magnetic flux tubes or loops. Due to the lack of contrast with their environment, observing and studying coronal loops in the quiet Sun is extremely difficult. In this work we use a differential…

Solar and Stellar Astrophysics · Physics 2022-08-17 C. Mac Cormack , M. López Fuentes , C. H. Mandrini , D. G. Lloveras , A. M. Vásquez

A three dimensional (3D) tomographic reconstruction of the local differential emission measure (LDEM) of the global solar corona during the whole heliosphere interval (WHI, Carrington rotation CR-2068) is presented, based on STEREO/EUVI…

Solar and Stellar Astrophysics · Physics 2015-05-20 Alberto M. Vásquez , Zhenguang Huang , Ward B. Manchester , Richard A. Frazin

We investigate the increase of the DEM (differential emission measure) towards the chromosphere due to small and cool magnetic loops (height $\lesssim8$~Mm, $T\lesssim10^5$~K). In a previous paper we analysed the conditions of existence and…

Solar and Stellar Astrophysics · Physics 2015-10-28 C. Sasso , V. Andretta , D. Spadaro

We use Solar Dynamics Observatory (SDO)/Atmospheric Imaging Assembly (AIA) data to reconstruct the plasma properties from differential emission measure (DEM) analysis for a previously studied long-lived, low-latitude coronal hole (CH) over…

Solar and Stellar Astrophysics · Physics 2020-01-15 Jonas Saqri , Astrid M. Veronig , Stephan G. Heinemann , Stefan J. Hofmeister , Manuela Temmer , Karin Dissauer , Yang Su

In this paper a new efficient algorithm for computation of radio wave ray trajectories is described. The algorithm is based on an original second-order difference scheme with a specific "length-conservation" property, which allows to…

Instrumentation and Methods for Astrophysics · Physics 2010-10-19 Leonid Benkevitch , Igor Sokolov , Divya Oberoi , Thomas Zurbuchen

We present an extension of the Coronal Reconstruction Onto B-Aligned Regions (CROBAR) method to Linear Force Free Field (LFFF) extrapolations, and apply it to the reconstruction of a set of AIA, MDI, and STEREO EUVI data. The results…

Solar and Stellar Astrophysics · Physics 2026-01-29 Joseph Plowman , Daniel B. Seaton , Amir Caspi , J. Marcus Hughes , Matthew J. West

The precise reconstruction of properties of photons and electrons in modern high energy physics detectors, such as the CMS or Atlas experiments, plays a crucial role in numerous physics results. Conventional geometrical algorithms are used…

High Energy Physics - Experiment · Physics 2023-11-30 Polina Simkina , Fabrice Couderc , Julie Malclès , Mehmet Özgür Sahin

High resolution reconstruction of complicated objects from incomplete and noisy data can be achieved by solving modulation equations iteratively under physical constraints. This direct demodulation method is a powerful technique for dealing…

Astrophysics · Physics 2009-11-10 Ti-Pei Li , Mei Wu