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High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star. A major limitation for such direct imaging is the speckle noise that is induced from the…

Instrumentation and Methods for Astrophysics · Physics 2015-10-14 JiangPei Dou , DeQing Ren , YongTian Zhu , Xi Zhang

We introduce ADAM, the All-Data Asteroid Modelling algorithm. ADAM is simple and universal since it handles all disk-resolved data types (adaptive optics or other images, interferometry, and range-Doppler radar data) in a uniform manner via…

Earth and Planetary Astrophysics · Physics 2015-03-18 Matti Viikinkoski , Mikko Kaasalainen , Josef Durech

The brightness of the emission from coronal loops in the solar atmosphere is strongly dependent on the temperature and density of the confined plasma. After a release of energy, these loops undergo a heating and upflow phase, followed by a…

Solar and Stellar Astrophysics · Physics 2019-03-20 C. D. Johnston , S. J. Bradshaw

Introducing a reduced particle stiffness in discrete element method (DEM) allows for bigger time steps and therefore fewer total iterations in a simulation. Although this approach works well for dry non-adhesive particles, it has been shown…

Soft Condensed Matter · Physics 2018-10-17 Sheng Chen , Wenwei Liu , Shuiqing Li

Broad differential emission measure (DEM) distributions in the corona are a sign of multi-thermal plasma along the line-of-sight. Traditionally, this is interpreted as evidence of multi-stranded loops. Recently, however, it has been shown…

Solar and Stellar Astrophysics · Physics 2018-12-05 Tom Van Doorsselaere , Patrick Antolin , Kostas Karampelas

Computed tomography (CT) has been developed as a non-destructive technique for observing minute internal images of samples. It has been difficult to obtain photo-realistic (clean or clear) CT images due to various unwanted artifacts…

Quantum Physics · Physics 2023-09-12 Kyungtaek Jun

The problem of solar corona heating remains one of key puzzles in astrophysics for a few decades; but none of the proposed mechanisms can give a definitive answer to this question. As a result, the novel scenarios are still suggested. Here,…

Solar and Stellar Astrophysics · Physics 2020-05-15 Yurii V. Dumin

Our understanding of fundamental processes in the solar corona has been greatly progressed based on the space observations of SMM, Yohkoh, Compton GRO, SOHO, TRACE, RHESSI, and STEREO. We observe now acoustic waves, MHD oscillations,…

Astrophysics · Physics 2009-11-13 Markus J. Aschwanden

The heating of the Sun's corona has been explained by several different mechanisms including wave dissipation and magnetic reconnection. While both have been shown capable of supplying the requisite power, neither has been used in a…

Solar and Stellar Astrophysics · Physics 2018-02-20 Kai E. Yang , Dana W. Longcope , M. D. Ding , Yang Guo

Thermal plasma of solar atmosphere includes a wide range of temperatures. This plasma is often quantified, both in observations and models, by a differential emission measure (DEM). DEM is a distribution of the thermal electron density…

Solar and Stellar Astrophysics · Physics 2021-06-23 Gregory D. Fleishman , Alexey A. Kuznetsov , Enrico Landi

We describe a technique to derive constraints on the differential emission measure (DEM) distribution, a measure of the temperature distribution, of collisionally ionized hot plasmas from their X-ray emission line spectra. This technique…

Astrophysics · Physics 2009-11-10 Patrick S. Wojdowski , Norbert S. Schulz

A rotational modulator (RM) gamma-ray imager is capable of obtaining significantly better angular resolution than the fundamental geometric resolution defined by the ratio of detector diameter to mask-detector separation. An RM imager…

Instrumentation and Methods for Astrophysics · Physics 2010-10-15 B. Budden , G. L. Case , M. L. Cherry

There is a growing interest in reconstructing the density matrix of photoelectron wavepackets, in particular in complex systems where decoherence can be introduced either by a partial measurement of the system or through coupling with a…

Electron tomography is becoming an increasingly important tool in materials science for studying the three-dimensional morphologies and chemical compositions of nanostructures. The image quality obtained by many current algorithms is…

X-ray polarization is a powerful tool for unveiling the anisotropic characteristics of high-energy celestial objects. We present a novel imaging reconstruction method designed for hard X-ray polarimeters employing a Si CMOS sensor and coded…

Instrumentation and Methods for Astrophysics · Physics 2024-07-09 Tsubasa Tamba , Hirokazu Odaka , Taihei Watanabe , Toshiya Iwata , Tomoaki Kasuga , Atsushi Tanimoto , Satoshi Takashima , Masahiro Ichihashi , Hiromasa Suzuki , Aya Bamba

We consider the imaging problem of the reconstruction of a three-dimensional object via optical diffraction tomography under the assumptions of the Born approximation. Our focus lies in the situation that a rigid object performs an…

Numerical Analysis · Mathematics 2024-07-11 Robert Beinert , Michael Quellmalz

Orbital tomography has recently been established as a technique to reconstruct molecular orbitals directly from photoemission data using iterative phase retrieval algorithms. In this work, we present a detailed description of steps for…

In this article we show that the reconstructions of semiconductor surfaces can be determined using a genetic procedure. Coupled with highly optimized interatomic potentials, the present approach represents an efficient tool for finding and…

Materials Science · Physics 2009-11-10 F. C. Chuang , C. V. Ciobanu , V. B. Shenoy , C. Z. Wang , K. M. Ho

We develop an optimization-based approach to the problem of reconstructing temperature-dependent material properties in complex thermo-fluid systems described by the equations for the conservation of mass, momentum and energy. Our goal is…

Fluid Dynamics · Physics 2013-04-11 Vladislav Bukshtynov , Bartosz Protas

The coronagraph is an instrument enables the investigation of faint features in the vicinity of the Sun, particularly coronal mass ejections (CMEs). So far coronagraphic observations have been mainly used to determine the geometric and…

Solar and Stellar Astrophysics · Physics 2017-01-18 Kyuhyoun Cho , Jongchul Chae , Eun-kyung Lim , Kyung-suk Cho , Su-Chan Bong , Heesu Yang