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Images captured from a long distance suffer from dynamic image distortion due to turbulent flow of air cells with random temperatures, and thus refractive indices. This phenomenon, known as image dancing, is commonly characterized by its…

计算机视觉与模式识别 · 计算机科学 2024-08-30 Ripon Kumar Saha , Esen Salcin , Jihoo Kim , Joseph Smith , Suren Jayasuriya

Advanced adaptive optics (AO) instruments on ground-based telescopes require accurate knowledge of the atmospheric turbulence strength as a function of altitude. This information assists point spread function reconstruction, AO temporal…

In this paper we describe the method of measurement of optical turbulence in twilight with MASS-DIMM. Some results of such observations carried out with SAI ASM installed on Mt. Shatdzatmaz: 1) characteristics of optical turbulence don't…

天体物理仪器与方法 · 物理学 2015-03-17 Boris Safonov

Our knowledge of the circumgalactic medium (CGM) is mostly based on quasar absorption-line measurements. These have uncovered a multiphase medium that is likely highly turbulent, but constraints of this turbulence are limited to…

星系天体物理 · 物理学 2023-08-24 Brad Koplitz , Edward Buie , Evan Scannapieco

Observations of ion-scale (k_y*rho_i <= 1) density turbulence of relative amplitude dn_e/n_e <= 0.2% are available on the Mega Amp Spherical Tokamak (MAST) using a 2D (8 radial x 4 poloidal channel) imaging Beam Emission Spectroscopy (BES)…

等离子体物理 · 物理学 2014-01-08 A R Field , D Dunai , Y-c Ghim , P Hill , B McMillan , C M Roach , S Saarelma , A A Schekochihin , S Zoletnik , the MAST team

Magnetohydrodynamic (MHD) turbulence in neutron star (NS) merger remnants can impact their evolution and multimessenger signatures, complicating the interpretation of present and future observations. Due to the high Reynolds numbers and the…

高能天体物理现象 · 物理学 2020-07-30 David Radice

We use three-dimensional numerical hydrodynamic simulations of the turbulent, multiphase atomic interstellar medium (ISM) to construct and analyze synthetic HI 21 cm emission and absorption lines. Our analysis provides detailed tests of 21…

星系天体物理 · 物理学 2015-06-19 Chang-Goo Kim , Eve C. Ostriker , Woong-Tae Kim

Results of 3-month continuous monitoring of turbulence profile and seeing at Cerro Tololo (Chile) in May-July 2002 are presented. Some 28000 low-resolution profiles were measured by a new MASS single-star turbulence monitor, accompanied by…

天体物理学 · 物理学 2009-11-07 A. Tokovinin , S. Baumont , J. Vasquez

Dealing numerically with the turbulent nature and non-linearity of the physical processes involved in the ISM requires the use of sophisticated numerical schemes coupled to HD and MHD mathematical models. SNe are the main drivers of the…

天体物理学 · 物理学 2007-05-23 Miguel A. de Avillez , Dieter Breitschwerdt

We present optical turbulence profiles obtained with a Generalized SCIDAR (G-SCIDAR) and a Low Layer SCIDAR (LOLAS) at the Observatorio Astron\'omico Nacional in San Pedro M\'artir (OAN-SPM), Baja California, Mexico, during three observing…

COupled SLope and scIntillation Detection And Ranging (CO-SLIDAR) is a recent profiling method of the vertical distribution of atmospheric turbulence strength ($C_n^2$ profile). It takes advantage of correlations of slopes and of…

大气与海洋物理 · 物理学 2015-06-18 Juliette Voyez , Clélia Robert , Jean-Marc Conan , Laurent M. Mugnier , Etienne Samain , Aziz Ziad

Although many long-range imaging systems are designed to support extended vision applications, a natural obstacle to their operation is degradation due to atmospheric turbulence. Atmospheric turbulence causes significant degradation to…

计算机视觉与模式识别 · 计算机科学 2022-09-21 Nithin Gopalakrishnan Nair , Kangfu Mei , Vishal M. Patel

Adaptive optics (AO) systems using tomographic estimation of three-dimensional structure of atmospheric turbulence requires vertical atmospheric turbulence profile, which describes turbulence strength as a function of altitude as a prior…

天体物理仪器与方法 · 物理学 2021-04-21 Hajime Ogane , Masayuki Akiyama , Shin Oya , Yoshito Ono

Radiation transport plays important roles in stellar atmospheres, but the effects of turbulence are being obscured by other effects such as stratification. Using radiative hydrodynamic simulations of forced turbulence, we determine the…

流体动力学 · 物理学 2021-09-29 Axel Brandenburg , Upasana Das

Adaptive optics (AO) is a technology in modern ground-based optical telescopes to compensate the wavefront distortions caused by atmospheric turbulence. One method that allows to retrieve information about the atmosphere from telescope data…

天体物理仪器与方法 · 物理学 2018-04-04 Tapio Helin , Stefan Kindermann , Jonatan Lehtonen , Ronny Ramlau

We introduce a novel technique to mitigate the adverse effects of atmospheric turbulence on astronomical imaging. Utilizing a video-to-image neural network trained on simulated data, our method processes a sliding sequence of short-exposure…

天体物理仪器与方法 · 物理学 2024-05-09 Spencer Bialek , Emmanuel Bertin , Sébastien Fabbro , Hervé Bouy , Jean-Pierre Rivet , Olivier Lai , Jean-Charles Cuillandre

Atmospheric turbulence characterization is crucial for technologies like free-space optical communications. Existing methods using a spatially-integrated one-dimensional (1D) orbital angular momentum (OAM) spectrum, P(m), obscure the…

光学 · 物理学 2025-09-09 Wenjie Jiang , Mingjian Cheng , Lixin Guo , Andrew Forbes

One native source of quality deterioration in medical imaging, and especially in our case optical coherence tomography (OCT), is the turbid biological media in which photon does not take a predictable path and many scattering events would…

图像与视频处理 · 电气工程与系统科学 2020-11-26 Ali Alavi

The altitude distribution of optical turbulence is derived from the MASS instrument data by solving an inverse problem. In this paper, some modifications of the profile restoration are described. The principal change is the introduction of…

天体物理仪器与方法 · 物理学 2011-01-13 V. Kornilov , M. Kornilov

One of the scientific goals of the Large Synoptic Survey Telescope (LSST) is to measure the evolution of dark energy by measuring subtle distortions of galaxy shapes due to weak gravitational lensing caused by the evolving dark matter…

天体物理仪器与方法 · 物理学 2018-07-27 Claire-Alice Hébert , Bruce Macintosh , Patricia R. Burchat