On-line atomic data access

1996 ◽  
Author(s):  
David R. Schultz ◽  
Jeffrey K. Nash
Keyword(s):  
Data Access ◽  
Atomic Data ◽  
On Line

scholarly journals DIVISION XII / COMMISSION 14 / WORKING GROUP ATOMIC DATA

2008 ◽  
Vol 4 (T27A) ◽  
pp. 375-384
Author(s):  
Gillian Nave ◽  
Glenn M. Wahlgren ◽  
Jeffrey R. Fuhr
Keyword(s):  
Experimental Data ◽  
Hyperfine Structure ◽  
Atomic Number ◽  
Working Group ◽  
Atomic Data ◽  
Laboratory Research ◽  
Data Bases ◽  
Line Structure ◽  
Original Laboratory ◽  
On Line

The references cited in this section are mostly papers on original laboratory research; compilations and data bases are covered in another section. The references, ordered by atomic number and spectrum, are given in parentheses following the spectral notations. References including experimental data on line structure, hyperfine structure (HFS) or isotope structure (IS) are also included.

scholarly journals Parametric potential for modelling of highly charged heavy ions

1996 ◽  
Vol 14 (4) ◽  
pp. 575-586 ◽  
Author(s):  
S. Mabong ◽  
G. Maynard ◽  
K. Katsonis
Keyword(s):  
Cross Sections ◽  
Heavy Ions ◽  
Inertial Confinement Fusion ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Inertial Confinement ◽  
Excitation Energies ◽  
Confinement Fusion ◽  
Self Consistent Field ◽  
On Line

Parametric electron-ion potential for fast estimation of atomic data required for “on-line” calculations in inertial confinement fusion (ICF) driven by heavy ions is presented. Comparisons of our results (outer- and inner-shell ionization energies, oscillator strengths, and logarithmic mean excitation energies) with experimental and self-consistent-field (SCF) calculation values are made. Using the wave functions generated by the previously mentioned potential, generalized oscillator strengths and integrated inelastic collision cross sections are computed within the frame of Born approximation.

scholarly journals The OPAL opacity Code

1995 ◽  
Vol 10 ◽  
pp. 573-573 ◽  
Author(s):  
F.J. Rogers ◽  
C.A. Iglesias
Keyword(s):  
Equation Of State ◽  
Cross Sections ◽  
Potential Method ◽  
Thomson Scattering ◽  
Mechanical Analysis ◽  
Atomic Data ◽  
Collective Effects ◽  
Line Broadening ◽  
On Line ◽  
Computationally Intensive

The OPAL opacity effort was undertaken in 1985 in response to speculation that the existing opacity data were not of sufficient accuracy to model observed stellar properties. We have taken the view that a completely new code with improved equation of state, atomic physics and line broadening was required. It was apparent that the most computationally intensive part of the calculations would be to obtain the vast amount of atomic data needed for the bound-bound and bound-free absorption cross-sections. To meet this challenge we developed a parametric potential method, that was fast enough to allow on-line calculations, while achieving accuracy comparable to that of the single-configuration Dirac-Fock method. This on-line capability was also chosen to allow flexibility to study the effect of various coupling and data averaging methods. It also makes it easy to study the effect of adding more elements.The OPAL equation of state is based on the many-body statistical mechanics of partially ionized plasmas in the grand canonical ensemble. This is the so-called “physical picture” method. In this approach one works directly with the electrons and nuclei present in the plasma. The effect of the plasma environment on the internal states is obtained directly from the statistical mechanical analysis. A convergent partition function is a natural consequence of this approach.OPAL includes degeneracy and plasma collective effects in the free-free absorption using a screened form of the parametric potentials. Similar corrections to the Thomson scattering are obtained from the method of Boercker (1987). The spectral line broadening for one, two and three electrons ions are obtained from a suite of codes provided by R.W. Lee (1988) that include linear Stark theory. For all other transitions we use Voigt profiles where the Gaussian width is due to Doppler broadening and the Lorentz width is due to the natural width plus fits to the electron impact collision width (Dimitrievic and Konjevic 1980).

scholarly journals Atmospheres and Winds of Hot Stars - Impacts of New Opacity Calculations and Continuing Needs

1995 ◽  
Vol 10 ◽  
pp. 585-587
Author(s):  
Keith Butler
Keyword(s):  
Linearization Method ◽  
Spectral Lines ◽  
The Other ◽  
Atomic Data ◽  
Stellar Winds ◽  
Function Concept ◽  
Hot Stars ◽  
Other Hand ◽  
Recent Developments ◽  
On Line

In this paper I review some recent advances in the use of large amounts of atomic data in the modelling of atmospheres and winds of hot stars. The review is highly selective but representative of current developments. A more general overview is to be found in Kudritzki and Hummer (1990) although the field is changing so rapidly that much has happened since then. The paper breaks down into three parts: work on line formation, in which the atmospheric structure is known and held fixed, is described first, then follows a description of the inclusion of line opacities in non-LTE in the atmosphere problem itself, and finally recent developments in the theory of radiatively driven stellar winds are summarized. Here special emphasis is given to a novel distance determination method based entirely on spectroscopie quantities. I close with a brief shopping list.In a series of papers, Becker and Butler (1992,1994a, b,c) have investigated iron and nickel spectra in sub-dwarfs using the complete linearization method of Auer and Heasley (1976). The method scales linearly with the number of frequency points so they were able to use well over 10000 frequencies to adequately describe the line opacities. Several thousand lines were treated explicitly and the resultant computed spectra gave execellent fits to observed Hubble spectra in the wavelength ranges dominated by the ions concerned.The different ionization stages gave consistent results for the iron and nickel abundances but only after line-blocking from millions of spectral lines in the far UV had been included. This was done using the Kurucz (1988) line lists coupled with line grouping as suggested by Anderson (1989) and described briefly in the next section.The line-blanketed atmospheres of Kurucz (1991) are the best available up to about 30000K, where non-LTE effects start to become important. Non-LTE line-blanketed atmospheres have become feasible because the computational requirements of the accelerated lambda iteration (ALI) method (Werner and Husfeld, 1985) also scale linearly with the number of frequency points. On the other hand, Anderson (1989) suggested grouping energetically adjacent atomic levels together to form pseudo-levels on the basis that although they might, as a group, be in non-LTE, they should be in LTE with respect to one another due to the large number of collisions between them. This greatly reduces the number of levels to be considered but instead gives rise to highly complicated pseudo line-profiles. Grigsby et al (1992), who did not use ALI, constructed the first grid of line-blanketed non-LTE models by using a variation on the Opacity Distribution Function concept to group line opacities into blocks thereby reducing the number of frequency points required. Dreizler and Werner (1993) on the other hand were able to sample the opacity as they used ALI in their models.

scholarly journals The ORFEUS Data Center

1994 ◽  
Vol 37 (5) ◽  
Author(s):  
B. Dost
Keyword(s):  
The Netherlands ◽  
Data Center ◽  
Data Centers ◽  
Data Access ◽  
High Quality ◽  
On Line ◽  
Key Issues ◽  
Access And Quality ◽  
The University ◽  
Meteorological Institute

1993 the ORFEUS Data Center (ODC; Dost, 1991) changed hosting organisation. It moved within the Netherlands from the University of Utrecht to the Royal Netherlands Meteorological Institute (KNM1) in de Bilt. This change in hosting organisation was necessary to ensure a longer term stability in the operation of the ODC. Key issues for the ODC are the rapid on-line data access and quality controlled, complete and efficient off-line data access. During 1992 the ODC became the European node in the international SPYDER system which provides near real-time access to digital broadband data from selected high quality stations. Electronic messages trigger soveral centers well distributed over the globe. These centers then collect the data by modem from selected stations in their region. Finally, data are distributed between data centers over internet.

scholarly journals The Working Group III on data exchange

1994 ◽  
Vol 37 (5) ◽  
Author(s):  
B. Dost
Keyword(s):  
Data Center ◽  
Data Exchange ◽  
Data Centers ◽  
Data Access ◽  
Group Iii ◽  
On Line ◽  
Key Issues ◽  
Access And Quality ◽  
The University ◽  
Meteorological Institute

n 1993 the ORFEUS Data Center (ODC; Dost, 1991) changed hosting organisation. It moved within the Netherlands from the University of Utrecht to the Royal Netherlands Meteorological Institute (KNM1) in de Bilt. This change in hosting organisation was necessary to ensure a longer term stability in the operation of the ODC. Key issues for the ODC are the rapid on-line data access and quality controlled, complete and efficient off-line data access. During 1992 the ODC became the European node in the international SPYDER system which provides near real-time access to digital broadband data from selected high quality stations. Electronic messages trigger soveral centers well distributed over the globe. These centers then collect the data by modem from selected stations in their region. Finally, data are distributed between data centers over internet.

scholarly journals Summary of the IRON and OPACITY Projects

1995 ◽  
Vol 10 ◽  
pp. 571-572
Author(s):  
Keith A. Berrington
Keyword(s):  
Cross Sections ◽  
Electron Excitation ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Resonance Structure ◽  
Quantum Numbers ◽  
Sufficient Detail ◽  
Excitation Cross Sections ◽  
Light Ions ◽  
On Line

Considerable effort has been made recently by international collaborations, exploiting advances in atomic physics and in supercomputing, to compute complete sets of accurate data for astrophysically important processes; in particular, the Opacity Project and the IRON Project.The Opacity Project computed atomic data for opacity calculations• for H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe.• energies of terms having effective quantum numbers v≤10 and total angular momentum L≤3 or 4, all spin and parity combinations;• gƒ-values for all dipole transitions between these bound terms;• total cross sections for photoionizaion from all calculated bound terms, tabulated on a grid of photon energies suitable to describe the resonance structure in sufficient detail to calculate reliable opacities;• line broadening parameters.28 key research papers arising from the Project, together with calculated energies and oscillator strengths for light ions, are reprinted in ‘The Opacity Project Volume 1’ (Opacity Project Team, 1994, IOP Publ. ISBN 0 7503 0288 7). All data are available from TOPbase, an on-line database at the CDS (Cunto et al. 1993, A&A 275, L5).The IRON Project aims to systematically compute electron excitation cross sections for the iron group of elements. Particular attention is given to requirements for the interpretation of data from specific space observations.In the first stage of the Project excitation cross sections have been computed for fine-structure transitions in the ground configuration of all ions of astrophysical interest. These data are essential for the interpretation of IR lines to be observed by ISO, as well as for coronal spectra.

On-Line Approaches to Data Delivery and Visualisation in Landscape Planning and Management

2012 ◽  
Vol 1 (1) ◽  
pp. 31-41 ◽  
Author(s):  
Ian D. Bishop
Keyword(s):  
Landscape Planning ◽  
Data Access ◽  
Data Delivery ◽  
Collaborative Virtual Environment ◽  
Specific Data ◽  
The Public ◽  
On Demand ◽  
Planning And Management ◽  
On Line ◽  
Cooperative Decision Making

Those involved in planning and management in landscape have long recognised the value of good information provided in the form of timely, appropriate and digestible data. Whether the data is part of government infrastructure or is augmented by contributions from the public, it is apparent that on-line delivery can help ensure that the best available data is accessible while visualisation techniques can make the data easier to interpret. A collaborative virtual environment then allows for cooperative decision-making in a well informed situation. Add smartphones into the technology mix and augmented reality presentation allows for in-field collaboration and also on-demand location specific data access and capture. A series of projects are described which illustrate this potential. A scenario for application in a situation of emergency management in the landscape concludes the paper.

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