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Related papers: Laboratory Photoionization Fronts in Nitrogen Gas:…

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Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by intense radiation is a key to understanding compact objects, such as black holes, based on astronomical observations. This paper describes an experiment to study…

Photoionization by the high-redshift ultraviolet radiation background heats low density gas before it falls into dark matter potential wells, and it eliminates the neutral hydrogen and singly ionized helium that dominate cooling of…

Astrophysics · Physics 2011-08-17 Anne A. Thoul , David H. Weinberg

Streamer discharges play a central role in electric breakdown of matter in pulsed electric fields, both in nature and in technology. Reliable and fast computations of the minimal model for negative streamers in simple gases like nitrogen…

Plasma Physics · Physics 2007-07-24 Alejandro Luque , Ute Ebert , Carolynne Montijn , Willem Hundsdorfer

Photoionized gases are prevalent throughout the universe. In such gases, the ion concentration typically exhibits two response modes to radiation: a positive response in the low-ionization state and a negative response in the…

Astrophysics of Galaxies · Physics 2025-06-02 Zhicheng He , Tinggui Wang , Gary J. Ferland

Realistic modeling of stellar spectra requires accurate radiative opacity coefficients. Owing to the fragmentary nature of existing data from rigorous quantum-mechanical calculations, photoionization coefficients based on the…

Solar and Stellar Astrophysics · Physics 2026-04-22 René D. Rohrmann

We report measurements of the electron temperature at about a dozen locations in the extended emission-line regions of five active (Seyfert and radio) galaxies. Temperatures (T_{[OIII]} and T_{[NII]}) have been determined from both the…

Astrophysics · Physics 2016-08-30 A. S. Wilson , L. Binette , T. Storchi-Bergmann

Photoionization by high-energy photons creates nonthermal electrons with a broad range of energies that heat and chemically transform the atmospheres of planets. The specifics of the interactions are notably different when the gas is atomic…

Earth and Planetary Astrophysics · Physics 2025-06-17 Antonio García Muñoz , Ewan Bataille

Observations of H2 line emission have revealed higher-than-expected gas temperatures in a number of photodissociation fronts. We discuss the heating and cooling processes in photodissociation regions. Observations of NGC 2023 are compared…

Astrophysics · Physics 2007-05-23 B. T. Draine , Frank Bertoldi

We present a new hybrid code for large volume, high resolution simulations of cosmic reionization, which utilizes a N-body algorithm for dark matter, physically motivated prescriptions for baryons and star formation, and an adaptive ray…

Astrophysics · Physics 2009-11-11 Hy Trac , Renyue Cen

We present numerical simulations of ultrafast multiphoton ionization dynamics in a two-dimensional atomic model driven by co- and counterrotating circularly polarized single-color and bichromatic carrier envelope phase (CEP) stable…

Atomic Physics · Physics 2020-07-15 T. Bayer , Ch. Philipp , K. Eickhoff , M. Wollenhaupt

In this paper we report on a detailed study of ionization signals produced by Compton electrons and alpha-particles in a Time Projection Chamber (TPC) flled with different mixtures of liquid Argon and Nitrogen. The measurements were carried…

Instrumentation and Detectors · Physics 2011-03-28 M. Zeller , I. Badhrees , S. Delaquis , A. Ereditato , S. Janos , I. Kreslo , M. Messina , U. Moser , B. Rossi

It is demonstrated that recent experiments on ionization of 3p and 3s electrons in Ni film and solid body cannot be described in the frames of Hartree-Fock or the random phase approximation with exchange. The deviation is so big that from…

Atomic Physics · Physics 2015-06-15 Miron Ya. Amusia , Larissa V. Chernysheva , Victor G. Yarzhemsky

An electron-impact ion source based on photoelectron emission was developed for ionization of gases at pressures below 1e-4 mbar in an axial magnetic field in the order of 5 T. The ion source applies only DC fields, which makes it suitable…

Instrumentation and Detectors · Physics 2011-01-25 S. Lukic , B. Bornschein , G. Drexlin , F. Glück , O. Kazachenko , M. Schöppner , Ch. Weinheimer , M. C. R. Zoll

When the neutral interstellar medium is exposed to EUV and soft X ray radiation, the argon atoms in it are far more susceptible to being ionized than the hydrogen atoms. We make use of this fact to determine the level of ionization in the…

Astrophysics of Galaxies · Physics 2013-01-29 Edward B. Jenkins

We conduct a statistical analysis of the factors responsible for the variation in the ionization parameter (U) of high-redshift star-forming galaxies based on medium resolution JWST/NIRSpec observations obtained by the Cosmic Evolution…

Astrophysics of Galaxies · Physics 2023-08-02 Naveen A. Reddy , Michael W. Topping , Ryan L. Sanders , Alice E. Shapley , Gabriel Brammer

Ultrafast processes in matter, such as the electron emission following light absorption, can now be studied using ultrashort light pulses of attosecond duration ($10^{-18}$s) in the extreme ultraviolet spectral range. The lack of spectral…

Radio and X-ray emission from brown dwarfs suggest that an ionised gas and a magnetic field with a sufficient flux density must be present. We perform a reference study for late M-dwarfs, brown dwarfs and giant gas planet to identify which…

Earth and Planetary Astrophysics · Physics 2015-11-04 M. I. Rodriguez-Barrera , Ch. Helling , C. R. Stark , A. M. Rice

Using the SEDs of the weak AGNs 35 LINERs presented in a companion paper, we assess whether photoionization by the weak AGN can power the emission-line luminosities measured through the large (few-arcsecond) apertures used in ground-based…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Michael Eracleous , Jason A. Hwang , Helene M. L. G. Flohic

To elucidate the permeation of cosmic ultraviolet (UV) background radiation into a pregalactic cloud and subsequent ionization, the frequency-dependent radiative transfer equation is solved, coupled with the ionization process. A spherical…

Astrophysics · Physics 2009-10-30 Yukiko Tajiri , Masayuki Umemura

Trapped ions are a promising modality for quantum systems, with demonstrated utility as the basis for quantum processors and optical clocks. However, traditional trapped-ion systems are implemented using complex free-space optical…