Plasma environment effects on K lines of astrophysical interest. V. Universal formulae for ionization potential and K-threshold shifts.

Aims. Within the framework of compact-object accretion disks, we calculate plasma environment effects on the atomic structure and decay parameters used in the modeling of K lines in lowly charged iron ions, namely Fe II–Fe VIII. Methods. For this study, we used the fully relativistic multiconfiguration Dirac–Fock method approximating the plasma electron–nucleus and electron-electron screenings with a time-averaged Debye-Hückel potential. Results. We report modified ionization potentials, K-threshold energies, wavelengths, radiative emission rates, and Auger widths for plasmas characterized by electron temperatures and densities in the ranges 105 − 107 K and 1018 − 1022 cm−3. In addition, we propose two universal fitting formulae to predict the IP and K-threshold lowerings in any elemental ion. Conclusions. We conclude that the high-resolution X-ray spectrometers onboard the future XRISM and ATHENA space missions will be able to detect the lowering of the K edges of these Fe ions due to the extreme plasma conditions occurring in the accretion disks around compact objects.

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Plasma-environment effects on K lines of astrophysical interest

Astronomy and Astrophysics ◽

10.1051/0004-6361/201937088 ◽

2020 ◽

Vol 635 ◽

pp. A70

Author(s):

J. Deprince ◽

M. A. Bautista ◽

S. Fritzsche ◽

J. A. García ◽

T. R. Kallman ◽

...

Keyword(s):

Accretion Disks ◽

Plasma Electron ◽

Compact Objects ◽

Emission Rates ◽

Plasma Environment ◽

Black Hole Accretion ◽

Environment Effects ◽

Threshold Energies ◽

Hole Accretion ◽

Atomic Parameters

Aims. In the context of black-hole accretion disks, we aim to compute the plasma-environment effects on the atomic parameters used to model the decay of K-vacancy states in moderately charged iron ions, namely Fe IX – Fe XVI. Methods. We used the fully relativistic multiconfiguration Dirac–Fock method approximating the plasma electron–nucleus and electron–electron screenings with a time-averaged Debye–Hückel potential. Results. We report modified ionization potentials, K-threshold energies, wavelengths, radiative emission rates, and Auger widths for plasmas characterized by electron temperatures and densities in the ranges 105−107 K and 1018−1022 cm−3. Conclusions. This study confirms that the high-resolution X-ray spectrometers onboard the future XRISM and Athena space missions will be capable of detecting the lowering of the K edges of these ions due to the extreme plasma conditions occurring in accretion disks around compact objects.

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LENS - Laser Energy for Nuclear Science facility @ LNS

EPJ Web of Conferences ◽

10.1051/epjconf/202022702001 ◽

2020 ◽

Vol 227 ◽

pp. 02001

Author(s):

Carmen Altana ◽

Gaetano Lanzalone ◽

Annamaria Muoio ◽

Salvatore Tudisco

Keyword(s):

Nuclear Reactions ◽

Laser Energy ◽

Nuclear Science ◽

Astrophysical Interest ◽

Plasma Environment

A dedicated laboratory at Laboratori Nazionali del Sud (LNS) of Catania was realized with the aim to investigate nuclear reactions of astrophysical interest in plasma environment. In this contribution, the facility LENS (Laser Energy for Nuclear Science), useful to study laser- produced plasmas, will be described and some results will be presented.

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Plasma environment effects on K lines of astrophysical interest

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935075 ◽

2019 ◽

Vol 624 ◽

pp. A74 ◽

Cited By ~ 5

Author(s):

J. Deprince ◽

M. A. Bautista ◽

S. Fritzsche ◽

J. A. García ◽

T. R. Kallman ◽

...

Keyword(s):

Black Hole ◽

Electron Temperature ◽

Accretion Disks ◽

Atomic Structure ◽

Radiative Transition ◽

Ionization Potentials ◽

Plasma Environment ◽

Black Hole Accretion ◽

Environment Effects ◽

Hole Accretion

Aims. In the context of black-hole accretion disks, the main goal of the present study is to estimate the plasma environment effects on the atomic structure and radiative parameters associated with the K-vacancy states in ions of the oxygen isonuclear sequence. Methods. We used a time-averaged Debye–Hückel potential for both the electron–nucleus and the electron–electron interactions implemented in the fully relativistic multiconfiguration Dirac–Fock (MCDF) method. Results. Modified ionization potentials, K thresholds, Auger widths, and radiative transition wavelengths and rates are reported for O I–O VII in plasma environments with electron temperature and density ranges 105−107 K and 1018−1022 cm−3.

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Plasma environment effects on K lines of astrophysical interest

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935444 ◽

2019 ◽

Vol 626 ◽

pp. A83 ◽

Cited By ~ 8

Author(s):

J. Deprince ◽

M. A. Bautista ◽

S. Fritzsche ◽

J. A. García ◽

T. Kallman ◽

...

Keyword(s):

Accretion Disks ◽

Electron Plasma ◽

Compact Objects ◽

Emission Rates ◽

Astrophysical Plasmas ◽

X Ray ◽

Radiative Emission ◽

Plasma Environment ◽

Environment Effects ◽

Atomic Parameters

Aims. In the context of accretion disks around black holes, we estimate plasma-environment effects on the atomic parameters associated with the decay of K-vacancy states in highly charged iron ions, namely Fe XVII – Fe XXV. Methods. Within the relativistic multiconfiguration Dirac–Fock (MCDF) framework, the electron–nucleus and electron–electron plasma screenings were approximated with a time-averaged Debye–Hückel potential. Results. Modified ionization potentials, K thresholds, wavelengths, radiative emission rates, and Auger widths are reported for astrophysical plasmas characterized by electron temperatures and densities in the ranges 105 − 107 K and 1018 − 1022 cm−3, respectively. Conclusions. We conclude that the high-resolution microcalorimeters on board future X-ray missions such as XRISM and ATHENA are expected to be sensitive to the lowering of the iron K edge due to the extreme plasma conditions occurring in accretion disks around compact objects.

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Elastic scattering of electron in neutral plasma: Interaction model and plasma environment effects

Physics of Plasmas ◽

10.1063/5.0017977 ◽

2020 ◽

Vol 27 (11) ◽

pp. 112701

Author(s):

W. L. Quan ◽

X. W. Sun ◽

Q. F. Chen

Keyword(s):

Elastic Scattering ◽

Interaction Model ◽

Plasma Interaction ◽

Plasma Environment ◽

Environment Effects ◽

Neutral Plasma

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Recent Radiative and Collisional Atomic Data of Astrophysical Interest

International Astronomical Union Colloquium ◽

10.1017/s0252921100107596 ◽

1988 ◽

Vol 102 ◽

pp. 129-132

Author(s):

K.L. Baluja ◽

K. Butler ◽

J. Le Bourlot ◽

C.J. Zeippen

Keyword(s):

Mass Production ◽

Bound States ◽

Physical Models ◽

Impact Excitation ◽

Electron Impact Excitation ◽

Atomic Data ◽

Isoelectronic Sequence ◽

Astrophysical Interest ◽

Radiative Transitions ◽

Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

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An Attack on the Contamination Problem in the Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061859 ◽

1967 ◽

Vol 25 ◽

pp. 368-368

Author(s):

J. J. Kelsch ◽

A. Holtz

Keyword(s):

Electron Microscope ◽

Pressure Gradient ◽

Ionization Potential ◽

Simple Solution ◽

Specimen Surface ◽

Contamination Rate ◽

Local Pressure ◽

High Ionization ◽

Hydrocarbon Molecules ◽

Contamination Problem

A simple solution to the serious problem of specimen contamination in the electron microscope is presented. This is accomplished by the introduction of clean helium into the vacuum exactly at the specimen position. The local pressure gradient thus established inhibits the migration of hydrocarbon molecules to the specimen surface. The high ionization potential of He permits the use of relatively large volumes of the gas, without interfering with gun stability. The contamination rate is reduced on metal samples by a factor of 10.

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