X-ray diagnostics for fusion plasmas

We have developed medium and high resolution X-ray crystal spectrometers for measurements of charge state distributions of impurity ions, density of suprathermal electrons and ion temperature in magnetically confined plasmas. The techniques utilizing these spectrometers are, in principle, applicable to laser produced plasmas, especially in their expanding phase. The role of X-ray spectroscopy to produce useful data for atomic physics as well as for plasma diagnostics is emphasized. A beam-line has been designed and installed to the Ultraviolet Synchrotron Radiation Facility (UVSOR) at IMS, Okazaki, for the purpose of establishing calibration techniques for optical components, detectors and spectrometers in the range from ultraviolet to soft X ray for plasma diagnostics. Characteristics of the beam and its application to the study of interaction between synchrotron radiation and hot dense plasmas are described. Synchrotron radiation can replace the dye laser which has so far been used as a light source in the laser-induced fluorescence method to obtain population density of specified levels in a plasma.

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SPACE-RESOLVING VUV AND SOFT X-RAY SPECTROSCOPY IN THE TANDEM MIRROR GAMMA 10 PLASMA

Surface Review and Letters ◽

10.1142/s0218625x02002634 ◽

2002 ◽

Vol 09 (01) ◽

pp. 555-559 ◽

Cited By ~ 4

Author(s):

M. YOSHIKAWA ◽

Y. OKAMOTO ◽

E. KAWAMORI ◽

Y. WATANABE ◽

C. WATABE ◽

...

Keyword(s):

Vacuum Ultraviolet ◽

Radiation Power ◽

Emission Spectra ◽

High Energy ◽

Absolute Calibration ◽

Fusion Plasmas ◽

X Ray ◽

Confined Plasmas ◽

Tandem Mirror ◽

Impurity Ions

Vacuum ultraviolet (VUV) and soft X-ray (SX) spectroscopic measurements are important means to diagnose radiation power loss, impurity ion densities and effective charge of confined plasma, Z eff , in magnetically confined plasmas such as fusion plasmas. We have constructed space- and time-resolving flat-field VUV (150–1050Å) and SX (20–350Å) spectrographs by using aberration-corrected concave gratings with varied line spacing. Absolute calibration experiments have been conducted at the Photon Factory in the High Energy Accelerator Research Organization. Absolute sensitivities of the VUV and SX spectrographs have been obtained for the two (S and P) polarization geometries. Thus, absolute intensities of emission spectra from impurity ions can be measured together with their radial distributions in plasmas. The total radiation power was determined to be less than 6 kW within ±20% of error in our normal plasma operation. Density profiles of impurity ions were reduced by using absolute emissivities of impurity lines and a collisional-radiative model. Moreover, the value of Z eff is estimated to be 1.00 in the tandem mirror GAMMA 10 plasma.

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Spectra Due to Dielectronic Recombination

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00005344 ◽

1985 ◽

Vol 19 (2) ◽

pp. 158-158

Author(s):

J Dubau ◽

F Bely-Dubau

Keyword(s):

Excited State ◽

Plasma Diagnostics ◽

Dielectronic Recombination ◽

Plasma Electron ◽

Spectral Lines ◽

Physical Parameters ◽

Fusion Plasmas ◽

Target Electron ◽

Capture Process ◽

X Ray

Dielectronic recombination (DR) is an electron-ion process particularly effective in high temperature plasmas such as those observed in the Solar Corona, Supernovae remnants in fusion plasmas (Tokamak and laser produced plasmas). This process is a resonant capture process of projectile electrons by a target ion as one of the target electron is excited, thereby forming an intermediate autionising state which can decay radiatively to a singly excited state. DR plays an important role on the establishment of ionisation equilibrium in the plasma and is also responsible for spectral lines appearing as satellites of the resonance lines of the target ion. The analysis and interpretation of such satellite lines in terms of plasma diagnostics has been widely used in soft X-ray spectroscopy during the last decade, and has given reliable estimates of the physical parameters of the plasma (electron and ion temperatures and densities). In the case of H-like and He-like resonance lines, high resolution spectra have been obtained in Tokamak for Z = 14 - 28 and most of the satellites have been clearly identified. To help the reader to go further we give some references of solar studies 2, 3, 4, 0, Tokamak 6, 7, laser plasma 8, 9.

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Workshop summary on thermal management of x‐ray optical components for synchrotron radiation

Review of Scientific Instruments ◽

10.1063/1.1145627 ◽

1995 ◽

Vol 66 (2) ◽

pp. 2380-2382

Author(s):

Dennis M. Mills ◽

Andreas Freund ◽

Tetsuya Ishikawa

Keyword(s):

Synchrotron Radiation ◽

Thermal Management ◽

Optical Components ◽

X Ray ◽

Workshop Summary

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Spectroscopic analysis of short-pulse laser-produced plasmas

Laser and Particle Beams ◽

10.1017/s0263034600008314 ◽

1994 ◽

Vol 12 (3) ◽

pp. 455-462 ◽

Cited By ~ 2

Author(s):

J.P. Matte ◽

J.C. Kieffer ◽

M. Chaker ◽

C.Y. Côté ◽

Y. Beaudoin ◽

...

Keyword(s):

Spectroscopic Analysis ◽

Short Pulse ◽

Electron Distribution Function ◽

Line Broadening ◽

Ion Temperature ◽

Electronic Density ◽

X Ray ◽

Dense Plasmas ◽

Tantalum Target ◽

Short Pulse Laser

Experimental spectra of hot dense plasmas of aluminium produced by the interaction of a subpicosecond laser with solid targets at 1016 and 5 × 1017 W/cm2 are analyzed and discussed. A detailed analysis of the K-shell spectra is given through time-dependent calculations of atomic physics postprocessed to Fokker-Planck calculations of the laser-matter interaction. The non-Maxwellian character of the electron distribution function is shown. An evaluation of the electronic density and of the ion temperature 7i will be presented through Stark line broadening calculations. An X-ray spectrum from a Tantalum target also will be presented along with a preliminary interpretation.

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Direct Observation of Monolayer Zones in Al-wt 4% Cu

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178823 ◽

1990 ◽

Vol 48 (1) ◽

pp. 14-15

Author(s):

B. Jouffrey ◽

D. Dorignac ◽

A. Bourret

Keyword(s):

Solid Solution ◽

Synchrotron Radiation ◽

Direct Observation ◽

Supersaturated Solid Solution ◽

Original Model ◽

X Ray ◽

Image Position

Since the early works on GP zones and the model independently proposed by Preston and Guinier on the first steps of precipitation in supersaturated solid solution of aluminium containing a few percent of copper, many works have been performed to understand the structure of different stages in the sequence of precipitation.The scheme which is generally admitted can be drawn from a work by Phillips.In their original model Guinier and Preston analysed a GP zone as composed of a single (100) copperrich plane surrounded by aluminum atomic planes with a slightly shorter distance from the original plane than in the solid solution.From X-ray measurements it has also been shown that GP1 zones were not only copper monolayer zones. They could be up to a few atomic planes thick. Different models were proposed by Guinier, Gerold, Toman. Using synchrotron radiation, proposals have been recently made.

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