Spectroscopic analysis and modeling of tungsten EBIT and Z-pinch plasma experiments1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 599-608 ◽  
Author(s):  
G.C. Osborne ◽  
A.S. Safronova ◽  
V.L. Kantsyrev ◽  
U.I. Safronova ◽  
P. Beiersdorfer ◽  
...  
Keyword(s):  
Electron Beam ◽  
Charge State ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Oscillator Strengths ◽  
Charge Balance ◽  
International Colloquium ◽  
Pinch Plasma ◽  
Z Pinch

Spectral tungsten data taken on an electron beam ion trap (EBIT) at Lawrence Livermore National Laboratory are analyzed between 3 and 8 Å for electron beam energies between 2.5 and 4.1 keV. The advantage of using charge state balancing with the experimental EBIT spectra for the identification of lines is employed and discussed. Theoretical Hebrew University Lawrence Livermore Atomic Code (HULLAC) modeling is then benchmarked against the experimental EBIT results. In particular, Co-, Ni-, Zn-, Cu-, Ga-, and Ge-like transitions were modeled independently using HULLAC to aid in charge state balancing. This model is then compared with Z-pinch plasma data collected on Zebra, the 1.6 MA pulse power generator located in the Nevada Terawatt Facility at the University of Nevada, Reno. The model is used to calculate charge balance and average ionization levels of these experimental plasma results, with particular focus on planar tungsten arrays.

Tungsten spectroscopy at the Livermore electron beam ion trap facility1This review is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 571-580 ◽  
Author(s):  
J. Clementson ◽  
P. Beiersdorfer ◽  
G.V. Brown ◽  
M.F. Gu ◽  
H. Lundberg ◽  
...  
Keyword(s):  
Electron Beam ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Ion Traps ◽  
Oscillator Strengths ◽  
Radiative Properties ◽  
Experimental Investigations ◽  
Fusion Plasma ◽  
International Colloquium

The utilization of tungsten spectroscopy for diagnostics of magnetically confined fusion plasmas requires the radiative properties of tungsten ions to be accurately known. At the Lawrence Livermore National Laboratory, a program to gather spectroscopic data on tungsten ions has been initiated with the purpose to study spectral signatures and identify candidate fusion plasma diagnostics. In this paper, an overview of recent results from the Livermore WOLFRAM spectroscopy project is presented, which includes experimental investigations at the EBIT-I and SuperEBIT electron beam ion traps. In particular, the spectra of highly charged M- and L-shell tungsten ions have been studied. These investigations cover energy measurements of n = 2 to n = 2, 3 transitions in Ne-like W64+ through Li-like W71+ ions and soft X-ray measurements of n = 3 to n = 3, 4 transitions in M-shell ions with emphasis on the Ni-like W46+ and Si-like W60+ through Na-like W63+ ions. The measurements are complemented by atomic-structure calculations and spectral modeling using the Flexible Atomic Code (FAC).

scholarly journals The importance of EBIT data for Z-pinch plasma diagnostics

2008 ◽  
Vol 86 (1) ◽  
pp. 267-276 ◽  
Author(s):  
A S Safronova ◽  
V L Kantsyrev ◽  
P Neill ◽  
U I Safronova ◽  
D A Fedin ◽  
...  
Keyword(s):  
Electron Beam ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Theoretical Models ◽  
High Energy ◽  
High Energy Density ◽  
Strong Electron ◽  
Model Calculations ◽  
X Ray ◽  
Z Pinch

The results from the last six years of X-ray spectroscopy and spectropolarimetry of high-energy density Z-pinch plasmas complemented by experiments with the electron beam ion trap (EBIT) at the Lawrence Livermore National Laboratory (LLNL) are presented. The two topics discussed are the development of M-shell X-ray W spectroscopic diagnostics and K-shell Ti spectropolarimetry of Z-pinch plasmas. The main focus is on radiation from a specific load configuration called an “X-pinch”. In this work the study of X-pinches with tungsten wires combined with wires from other, lower Z materials is reported. Utilizing data produced with the LLNL EBIT at different energies of the electron beam the theoretical prediction of line positions and intensity of M-shell W spectra were tested and calibrated. Polarization-sensitive X-pinch experiments at the University of Nevada, Reno (UNR) provide experimental evidence for the existence of strong electron beams in Ti and Mo X-pinch plasmas and motivate the development of X-ray spectropolarimetry of Z-pinch plasmas. This diagnostic is based on the measurement of spectra recorded simultaneously by two spectrometers with different sensitivity to the linear polarization of the observed lines and compared with theoretical models of polarization-dependent spectra. Polarization-dependent K-shell spectra from Ti X-pinches are presented and compared with model calculations and with spectra generated by a quasi-Maxwellian electron beam at the LLNL EBIT-II electron beam ion trap.PACS Nos.: 32.30.Rj, 52.58.Lq, 52.70.La

Measurements and calculations of Zn-like heavy ions: an update1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 639-645 ◽  
Author(s):  
Elmar Träbert ◽  
Joel Clementson ◽  
Peter Beiersdorfer ◽  
Juan A. Santana ◽  
Yasuyuki Ishikawa
Keyword(s):  
Electron Beam ◽  
Heavy Ions ◽  
Ion Trap ◽  
Oscillator Strengths ◽  
Valence Shell ◽  
Special Issue ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
Electron Beam Ion Trap

Previous observations of Zn-like ions of elements Yb (Z = 70) through U (Z = 92) in an electron beam ion trap differed (by value and by isoelectronic trend) from the (less precise) results of laser-produced plasma experiments and highlighted the need for much better calculations of ions with more than one electron in the valence shell. We review the progress since achieved and present new calculations for ions in the above range as well as EBIT observations of Zn-like Pt48+ ions (Z = 78). We identify accurate ab initio calculations that agree with the EBIT data as well as recent calculations that clearly fall short.

Recent activities at the Tokyo EBIT 2006

2008 ◽  
Vol 86 (1) ◽  
pp. 315-319 ◽  
Author(s):  
N Nakamura ◽  
F J Currell ◽  
D Kato ◽  
A P Kavanagh ◽  
Y M Li ◽  
...  
Keyword(s):  
Electron Beam ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Ion Beams ◽  
Electron Beam Ion Trap ◽  
Highly Charged Ion

The electron beam ion trap (EBIT) in Tokyo was constructed about 10 years after the first EBIT at Lawrence Livermore National Laboratory was built, and has been being stably operated since then. In this paper, we present recent experimental activities at the Tokyo EBIT. In particular, experiments utilizing slow, very highly charged ion beams extracted from the EBIT are reported. PACS Nos.: 39.10.+j, 32.30.Rj, 34.50.Dy, 34.80.Kw

K-shell spectroscopy of Au plasma generated with a short-pulse laser1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 647-651 ◽  
Author(s):  
C. Zulick ◽  
F. Dollar ◽  
H. Chen ◽  
K. Falk ◽  
G. Gregori ◽  
...  
Keyword(s):  
Short Pulse ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Laser System ◽  
Oscillator Strengths ◽  
X Rays ◽  
Plasma Diagnostic ◽  
International Colloquium ◽  
X Ray ◽  
Population Distributions

The production of X-rays from electron transitions into K-shell vacancies (Kα,β) emission) is a well-known process in atomic physics and has been extensively studied as a plasma diagnostic in low- and mid-Z materials. However, X-ray spectra from near neutral high-Z ions are very complex, and their interpretation requires the use of state-of-the-art atomic calculations. In this experiment, the Titan laser system at Lawrence Livermore National Laboratory was used to deliver an approximately 350 J laser pulse, with a 10 ps duration and a wavelength of 1054 nm, to a gold (Au) target. A transparent bent quartz crystal spectrometer with a hard X-ray energy window, ranging from 17 to 102 keV, was used to measure the emission spectrum. Kα1,α2 and Kβ1,γ1 transitions were observed over a range of target sizes. Additionally, a series of shots were conducted with a pre-ionizing long pulse (3 ns, 1–10 J, 527 nm) on the backside of the target. FLYCHK, an atomic non-LTE code, designed to provide ionization and population distributions, was used to model the experiment. Kα/Kβ ratios were found to be in good agreement with the predicted value for room temperature Au targets.

The study of X-ray M-shell spectra of W ions from the Lawrence Livermore National Laboratory Electron Beam Ion Trap

2004 ◽  
Vol 82 (11) ◽  
pp. 931-942 ◽  
Author(s):  
P Neill ◽  
C Harris ◽  
A S Safronova ◽  
S Hamasha ◽  
S Hansen ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Range ◽  
Spectral Region ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Spectral Features ◽  
X Ray ◽  
Electron Beam Ion Trap

M-shell spectra of W ions have been produced at the Lawrence Livermore National Laboratory EBIT-II electron beam ion trap-II at different energies of the electron beam. A survey has been performed at 2.4, 2.8, and 3.6 keV, and for steps in energy of 100 eV over the 3.9–4.6 keV energy range. The analysis of 11 W spectra has shown the presence of a wide variety of ionization stages from Se-like to Cr-like W; the appearances of these ionization stages correlate well with the energy of their production. The present paper focuses on the identification of 63 experimental features of W ions in a spectral region from 5 to 6 Å (1 Å = 10–10 m) using calculations with inclusion of all ionization stages matching this spectral region. The majority of lines in all spectra have been identified and assigned to the 4f → 3d and 4d → 3p transitions. This is the first work that lists a comprehensive identification of so many resolved spectral features of X-ray M-shell transitions in W ions recorded in such detail in the laboratory. PACS Nos.: 52.58.Lq,32.30.Rj,52.70.La

A visible spectral survey from the Alcator C-Mod tokamak1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 615-626 ◽  
Author(s):  
A.T. Graf ◽  
M.J. May ◽  
P. Beiersdorfer
Keyword(s):  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Oscillator Strengths ◽  
Visible Emission ◽  
International Colloquium ◽  
10Th International Colloquium ◽  
Laboratory Plasmas ◽  
To Come ◽  
Low Charge ◽  
Spectral Survey

A visible spectral survey (3675–6744 Å) from the Alcator C-Mod tokamak has been performed using a high-resolution visible spectrometer constructed at the Lawrence Livermore National Laboratory. The Alcator C-Mod deuterium plasma is shown to have visible emission from numerous atomic species and low charge state ions including, D I, B II–III, B V, C II–III, N II–III, O II–IV, F II–III, Ne I, Na X, Al II–III, Si I–II, Cl II–III, Ar I–III, Ar X, Ti I and III, Fe I–III, Cu I, and III, Mo I, and W I. Nearly all of the emission is thought to come from the cooler edge of the plasma including the scrape-off layer, outside of the last closed magnetic flux surface. However, there is at least one example, included here, where intrinsic visible emission persists deeper into the plasma.

scholarly journals The XRS microcalorimeter spectrometer at the Livermore electron beam ion trap

2008 ◽  
Vol 86 (1) ◽  
pp. 231-240 ◽  
Author(s):  
F S Porter ◽  
B R Beck ◽  
P Beiersdorfer ◽  
K R Boyce ◽  
G V Brown ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Performance ◽  
Ion Trap ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
High Energy ◽  
Operating Conditions ◽  
Superconducting Detector ◽  
High Quantum Efficiency ◽  
Electron Beam Ion Trap

NASA’s X-ray spectrometer (XRS) microcalorimeter instrument has been operating at the electron beam ion trap (EBIT) facility at Lawrence Livermore National Laboratory since July of 2000. The spectrometer is currently undergoing its third major upgrade to become an easy to use and extremely high-performance instrument for a broad range of EBIT experiments. The spectrometer itself is broadband, capable of simultaneously operating from 0.1 to 12 keV and has been operated at up to 100 keV by manipulating its operating conditions. The spectral resolution closely follows the spaceflight version of the XRS, beginning at 10 eV FWHM at 6 keV in 2000, upgraded to 5.5 eV in 2003, and will hopefully be ~3.8 eV in the fall of 2007. Here we review the operating principles of this unique instrument, the extraordinary science that has been performed at EBIT over the last six years, and prospects for future upgrades. Specifically, we discuss upgrades to cover the high-energy band (to at least 100 keV) with a high quantum efficiency detector and prospects for using a new superconducting detector to reach 0.8 eV resolution at 1 keV and 2 eV at 6 keV with high counting rates. PACS Nos.: 52.25.Os, 52.70.La, 95.85.Nv, 32.30.Rj, 07.85.Fv, 78.70.En

Tungsten measurement on Alcator C-Mod and EBIT for future fusion reactors1This article is part of a Special Issue on the 10th International Colloquium on Atomic Spectra and Oscillator Strengths for Astrophysical and Laboratory Plasmas.

2011 ◽  
Vol 89 (5) ◽  
pp. 591-597 ◽  
Author(s):  
Y.A. Podpaly ◽  
J.E. Rice ◽  
P. Beiersdorfer ◽  
M.L. Reinke ◽  
J. Clementson ◽  
...  
Keyword(s):  
Ion Trap ◽  
Oscillator Strengths ◽  
Continuum Emission ◽  
Tokamak Plasmas ◽  
Ion Temperature ◽  
International Colloquium ◽  
Plasma Facing Components ◽  
Laboratory Plasmas ◽  
Electron Beam Ion Trap ◽  
Theoretical Predictions

Tungsten will be an important element in nearly all future fusion reactors because of its presence in plasma facing components. This makes tungsten a good candidate for a diagnostic element for ion temperature and toroidal velocity measurement, and it makes understanding tungsten emissions important for tokamak power balance. The effect of tungsten on tokamak plasmas is investigated at the Alcator C-Mod tokamak using VUV, bolometry, and soft X-ray spectroscopy. Tungsten was present in Alcator C-Mod as a plasma facing component and through laser blow-off impurity injection. Quasi-continuum emission previously seen at other tokamaks has been identified. Theoretical predictions are presented of tungsten emission that could be expected in future Alcator C-Mod measurements. Furthermore, spectra of highly charged tungsten ions have been studied at the SuperEBIT electron beam ion trap. This emission could prove useful for spectroscopic diagnostics of future high-temperature fusion reactor plasmas.

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