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We present a detailed model of the discrete X-ray spectroscopic features expected from steady-state, low-density photoionized plasmas. We apply the Flexible Atomic Code (FAC) to calculate all of the necessary atomic data for the full range…

Astrophysics · Physics 2007-05-23 A. Kinkhabwala , E. Behar , M. Sako , M. F. Gu , S. M. Kahn , F. B. S. Paerels

We investigate the angle-resolved photoelectron spectra from laser-assisted photoionization for helium and neon atoms using an \textit{ab initio} method based on time-dependent surface flux and configuration interaction singles. We find…

Atomic Physics · Physics 2020-08-26 Mattias Bertolino , David Busto , Felipe Zapata , Jan Marcus Dahlström

We demonstrate that the angular distribution of photoelectrons from a strongly polarizable target exposed to a laser field can deviate noticeably from the prediction of conventional theory. Even within the dipole-photon approximation the…

Atomic and Molecular Clusters · Physics 2009-11-13 A. V. Korol , A. V. Solov'yov

Radiative transfer coupled with highly realistic simulations of the solar atmosphere is routinely used to infer the physical properties underlying solar observations. Due to its computational efficiency, the method of short-characteristics…

Solar and Stellar Astrophysics · Physics 2018-04-17 Courtney L. Peck , Serena Criscuoli , Mark P. Rast

The emission of thermal radiation is a physical process of fundamental and technological interest. From different approaches, thermal radiation can be regarded either as one of the basic mechanisms of heat transfer, as a fundamental quantum…

Optics · Physics 2024-01-19 J. Enrique Vázquez-Lozano , Iñigo Liberal

The history of the magnetron and Penning electrode geometry is briefly outlined. Plasma generation by electrical discharge-driven electron impact ionization is described and the basic physics of plasma and electrodes relevant to magnetron…

Accelerator Physics · Physics 2014-04-04 D. C. Faircloth

The electromagnetic processes of Compton scattering and photon splitting/merging are investigated in the presence of strongly magnetized electron-positron plasma. The influence of these processes on the radiation transfer in the…

High Energy Physics - Phenomenology · Physics 2008-12-01 M. V. Chistyakov , D. A. Rumyantsev

The study of photoionised gas in planetary nebulae (PNe) has played a major role achieving, over the years, a better understanding of a number of physical processes pertinent to a broader range of fields than just PNe studies, ranging from…

Astrophysics · Physics 2009-11-11 Barbara Ercolano

Resonances, which are also described as autoionizing or quasi-bound states, play an important role in the scattering of atoms and ions with electrons. The current article is an overview of the main methods, including a recently-proposed…

Atomic Physics · Physics 2013-08-06 Taha Sochi , P. J. Storey

The Diffuse Ionised Gas (DIG) in galaxies traces photoionisation feedback from massive stars. Through three dimensional photoionisation simulations, we study the propagation of ionising photons, photoionisation heating and the resulting…

Astrophysics of Galaxies · Physics 2015-06-19 J. E. Barnes , Kenneth Wood , Alex S. Hill , L. M. Haffner

In previous work we have shown that positive streamers in pure nitrogen can be guided by a laser-induced trail of low electron density. Here we show more detailed results from such measurements. We show the sensitivity of this laser-guiding…

Plasma Physics · Physics 2016-02-26 S. Nijdam , E. Takahashi

We use a three-specie fluid model of electric discharge in air to simulate streamer evolution from the avalanche-to-streamer transition to the collision of opposite-polarity streamers. We estimate the upper limit on the production of…

Space Physics · Physics 2018-08-03 Nikolai G. Lehtinen , Nikolai Østgaard

A program to compute photo-ionization functions and fitting parameters for an efficient photo-ionization model is presented. The code integrates the product of spectrum emission intensity, the photo-ionization yield and the absorption…

Plasma Physics · Physics 2020-05-21 Yifei Zhu , Yun Wu , Jianzhong Li

We discuss the scattering of photons from a three-level emitter in a one-dimensional waveguide, where the transport is governed by the interference of spontaneously emitted and directly transmitted waves. The scattering problem is solved in…

Quantum Physics · Physics 2010-11-15 D. Witthaut , A. S. Sorensen

This paper proposes a method for estimating and detecting optical signals in practical photon-counting receivers. There are two important aspects of non-perfect photon-counting receivers, namely, (i) dead time which results in blocking…

Signal Processing · Electrical Eng. & Systems 2024-08-21 Chen Wang , Zhiyong Xu , Jingyuan Wang , Jianhua Li , Weifeng Mou , Huatao Zhu , Jiyong Zhao , Yang Su , Yimin Wang , Ailin Qi

The degradation of the acquired signal by Poisson noise is a common problem for various imaging applications, such as medical imaging, night vision and microscopy. Up to now, many state-of-the-art Poisson denoising techniques mainly…

Computer Vision and Pattern Recognition · Computer Science 2015-10-13 Wensen Feng , Yunjin Chen

Transfer-ionization in fast collisions between a bare ion and an atom, in which one of the atomic electrons is captured by the ion whereas another one is emitted, crucially depends on dynamic electron-electron correlations. We show that in…

Atomic Physics · Physics 2013-05-15 A. B. Voitkiv

The flow of ions through permeable channels causes voltage drop in physiological nanodomains such as synapses, dendrites and dendritic spines, and other protrusions. How the voltage changes around channels in these nanodomains has remained…

Soft Condensed Matter · Physics 2025-01-10 Frédéric Paquin-Lefebvre , David Holcman

Ptychography is a popular imaging technique that combines diffractive imaging with scanning microscopy. The technique consists of a coherent beam that is scanned across an object in a series of overlapping positions, leading to reliable and…

Numerical Analysis · Mathematics 2024-08-08 Ricardo Parada , Samy Wu Fung , Stanley Osher

X-ray is a ubiquitous imaging modality in clinical diagnostics and industrial inspections, thanks to its high penetration power. Conventional x-ray imaging system, equipped with energy-integrating detectors, collects approximately 1000 to…

Medical Physics · Physics 2020-08-24 Zheyuan Zhu , Shuo Pang
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