English
Related papers

Related papers: Ionospheric Power-Spectrum Tomography in Radio Int…

200 papers

A 3D tomographic reconstruction technique is described for inversion of a set of limited-angle high-resolution 2D visible light emission projections (extended in the vertical and toroidal directions) of global MHD eigenmodes in the H-1NF…

Plasma Physics · Physics 2014-08-29 S. R. Haskey , B. D. Blackwell , B. Seiwald , J. Howard

Radio astronomical imaging using aperture synthesis telescopes requires deconvolution of the point spread function as well as calibration of the instrumental characteristics (primary beam) and foreground (ionospheric/atmospheric) effects.…

Instrumentation and Methods for Astrophysics · Physics 2011-11-24 Juan M. Uson , William D. Cotton

The dynamic spectrum of a radio pulsar is an in-line digital hologram of the ionised interstellar medium. It has previously been demonstrated that such holograms permit image reconstruction, in the sense that one can determine an…

Astrophysics · Physics 2009-11-13 Mark Walker , Leon Koopmans , Dan Stinebring , Willem van Straten

We are aiming to identify the thin insulating inhomogeneities and small conductive inhomogeneities inside an electrically conducting medium by using multi-frequency electrical impedance tomography (mfEIT). The thin insulating…

Analysis of PDEs · Mathematics 2016-08-24 Habib Ammari , Jin Keun Seo , Tingting Zhang

In inertial confinement fusion (ICF), Thomson scattering (TS) is a widely used diagnostic technique for probing plasma conditions. We present a first-principles numerical approach to obtaining scattered light signals of ion acoustic…

High-redshift 21-cm observations will provide crucial insights into the physical processes of the Epoch of Reionization. Next-generation interferometers such as the Square Kilometer Array will have enough sensitivity to directly image the…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-27 Simon Gazagnes , Léon V. E. Koopmans , Michael H. F. Wilkinson

The spatial coherence wavefront outer scale (L_0) characterizes the size of the largest turbulence eddies in Earth's atmosphere, determining low spatial frequency perturbations in the wavefront of the light captured by ground-based…

Instrumentation and Methods for Astrophysics · Physics 2024-07-03 Begoña García-Lorenzo , Donaji Esparza-Arredondo , Jose A. Acosta-Pulido , Julio A. Castro-Almazán

In this work we consider the inverse problem of reconstructing the optical properties of a layered medium from an elastography measurement where optical coherence tomography is used as the imaging method. We hereby model the sample as a…

Numerical Analysis · Mathematics 2024-02-23 Peter Elbau , Leonidas Mindrinos , Leopold Veselka

Cool giant and supergiant star atmospheres are characterized by complex velocity fields originating from convection and pulsation processes which are not fully understood yet. The velocity fields impact the formation of spectral lines,…

Solar and Stellar Astrophysics · Physics 2018-02-21 K. Kravchenko , S. Van Eck , A. Chiavassa , A. Jorissen , B. Freytag , B. Plez

We apply tomography, a general method for reconstructing 3-D distributions from multiple projections, to reconstruct the momentum distribution of electrons produced via strong field photoionization. The projections are obtained by rotating…

Atomic Physics · Physics 2009-09-28 C Smeenk , L Arissian , A Staudte , D M Villeneuve , P B Corkum

This paper presents a case study from a single, six-hour observing period to illustrate the application of techniques developed for interferometric radio telescopes to the spectral analysis of observations of ionospheric fluctuations with…

Space Physics · Physics 2014-02-05 Joseph Helmboldt , Huib Intema

Interferometric methods, renowned for their reliability and precision, play a vital role in phase imaging. Interferometry typically requires high coherence and stability between the measured and the reference beam. The presence of rapid…

Spatio-temporally modulated impedance surfaces can be good candidates for generation of radiating waves with arbitrary eigenstates by breaking momentum and energy conservations. Here, we present a theoretical framework based on the…

Applied Physics · Physics 2021-12-16 Amrollah Amini , Homayoon Oraizi

Photoelectron spectroscopy is a powerful method that provides insight into the quantum mechanical properties of a wide range of systems. The ionized electron wavefunction carries information on the structure of the bound orbital, the ionic…

Interferometric imaging is a well established method to image phase objects by mixing the image wavefront with a reference one on a CCD camera. It has also been applied to fast transient phenomena, mostly through the analysis of single…

Thomson scattering of laser light is one of the most fundamental diagnostics of plasma density, temperature and magnetic fields. It relies on the assumption that the properties in the probed volume are homogeneous and constant during the…

Plasma Physics · Physics 2016-04-29 P. M. Kozlowski , B. J. B. Crowley , D. O. Gericke , S. P. Regan , G. Gregori

Turbulent dynamics generate random fluctuations in density and velocity in the Interstellar Medium (ISM) of spiral and dwarf galaxies. Observationally, H~{\sc i} 21-cm radiation provides a good probe of these stochastic processes and helps…

Astrophysics of Galaxies · Physics 2018-05-30 Meera Nandakumar

Arguments based on general principles of quantum mechanics suggest that a minimum length or time associated with Planck-scale unification may entail a new kind of observable uncertainty in the transverse position of macroscopically…

General Relativity and Quantum Cosmology · Physics 2010-01-09 Craig J. Hogan

Diffraction tomography is a widely used inverse scattering technique for quantitative imaging of weakly scattering media. In its conventional formulation, diffraction tomography assumes monochromatic plane wave illumination. This…

Numerical Analysis · Mathematics 2026-03-11 Peter Elbau , Noemi Naujoks , Otmar Scherzer

Radio emission propagating over an Earth-pulsar line of sight provides a unique probe of the intervening ionized interstellar medium (ISM). Variations in the integrated electron column density along this line of sight, or dispersion measure…

High Energy Astrophysical Phenomena · Physics 2020-04-08 M. T. Lam , T. J. W. Lazio , T. Dolch , M. L. Jones , M. A. McLaughlin , D. R. Stinebring , M. Surnis