Measurements of the intercombination and forbidden lines from the spectra of helium-like ions in tokamaks and electron beam ion traps

2008 ◽  
Vol 86 (1) ◽  
pp. 291-306 ◽  
Author(s):  
M Bitter ◽  
K W Hill ◽  
S von Goeler ◽  
W Stodiek ◽  
P Beiersdorfer ◽  
...  
Keyword(s):  
Electron Beam ◽  
Radial Profile ◽  
Historical Review ◽  
Ion Traps ◽  
X Ray ◽  
Spatially Resolved ◽  
X Ray Imaging ◽  
Radial Profiles ◽  
Theoretical Predictions ◽  
New Type

The paper reviews the results from tokamak experiments and measurements on electron beam ion traps for the line ratios x/w, y/w, and z/w in the spectra of helium-like ions with Z in the range from 14 to 28. With the exception of the DITE experiments, where these line ratios were found to be in agreement with theoretical predictions, all other tokamak experiments yielded values that were significantly greater than predicted. The reasons for these discrepancies are not yet understood. It is possible that radial profile effects were not properly taken into account in the majority of the tokamak experiments. The paper also gives a short historical review of the X-ray diagnostic developments and presents very recent data from a new type of X-ray imaging crystal spectrometer, which records spatially resolved spectra with a spatial resolution of about 1 cm in the plasma. These new data can be Abel inverted, so that it will be possible to determine line ratios at each radial position in the plasma. Effects of radial profiles, which may have affected the chord-integrated measurements of the past, will thus be eliminated in the future. PACS Nos.: 52.55.Fa, 32.30.Rj

The fundamental experiments x-ray imaging driven by electron beam

2012 ◽  
Author(s):  
Yoichiro Neo ◽  
Ryuji Suzuki ◽  
Toru Aoki ◽  
Hidenori Mmimura
Keyword(s):  
Electron Beam ◽  
X Ray ◽  
X Ray Imaging

Internal Strain Measurements and X-ray Imaging in Interpenetrating-Phase Al2O3/Al Composites

2004 ◽  
Vol 840 ◽  
Author(s):  
Marcus L. Young ◽  
Jon D. Almer ◽  
Ulrich Lienert ◽  
Kamel Fezzaa ◽  
Wah-Keat Lee ◽  
...  
Keyword(s):  
Load Transfer ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Lattice Strains ◽  
Alumina Phase ◽  
X Ray Imaging ◽  
Extent Of Damage ◽  
Liquid Metal Infiltration

ABSTRACTInterpenetrating Al2O3/Al composites were created by liquid-metal infiltration of alumina preforms with three-dimensional periodicity produced by a robotic deposition method. Volume-averaged lattice strains in the alumina phase were measured by synchrotron x-ray diffraction at various uniaxial compression stresses up to 350 MPa. Load transfer, which is experimentally found to occur between the aluminum and the alumina phase, is in agreement with simple rule of mixtures models. Spatially resolved measurements showed variations in load transfer at different positions within the composite for the elastic-, plastic-, and damage-deformation regimes. Using phase-enhanced imaging, the extent of damage within the composites was observed.

scholarly journals Magnetic field estimates from the X-ray synchrotron emitting rims of the 30 Dor C superbubble and the implications for the nature of 30 Dor C’s TeV emission

2019 ◽  
Vol 621 ◽  
pp. A138 ◽  
Author(s):  
Patrick J. Kavanagh ◽  
Jacco Vink ◽  
Manami Sasaki ◽  
You-Hua Chu ◽  
Miroslav D. Filipović ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Radial Profile ◽  
Emission Mechanism ◽  
X Ray ◽  
Point Spread ◽  
Radial Profiles ◽  
Upper Limits ◽  
Spread Function ◽  
Emissivity Model ◽  
Two Sectors

Context. The 30 Dor C superbubble is unique for its synchrotron X-ray shell, as well as being the first superbubble to be detected in TeV γ-rays, though which is the dominant TeV emission mechanism, leptonic or hadronic, is still unclear. Aims. We aim to use new Chandra observations of 30 Dor C to resolve the synchrotron shell in unprecedented detail and to estimate the magnetic (B) field in the postshock region, a key discriminator between TeV γ-ray emission mechanisms. Methods. We extracted radial profiles in the 1.5–8 keV range from various sectors around the synchrotron shell and fitted these with a projected and point spread function convolved postshock volumetric emissivity model to determine the filament widths. We then calculated the postshock magnetic field strength from these widths. Results. We find that most of the sectors were well fitted with our postshock model and the determined B-field values were low, all with best fits ≲20 μG. Upper limits on the confidence intervals of three sectors reached ≳30 μG though these were poorly constrained. The generally low B-field values suggests a leptonic-dominated origin for the TeV γ-rays. Our postshock model did not provide adequate fits to two sectors. We find that one sector simply did not provide a clean enough radial profile, while the other could be fitted with a modified postshock model where the projected profile falls off abruptly below ~0.8 times the shell radius, yielding a postshock B-field of 4.8 (3.7–11.8) μG which is again consistent with the leptonic TeV γ-ray mechanism. Alternatively, the observed profiles in these sectors could result from synchrotron enhancements around a shock–cloud interaction as suggested in previous works. Conclusions. The average postshock B-field determined around the X-ray synchrotron shell of 30 Dor C suggests the leptonic scenario as the dominant emission mechanism for the TeV γ-rays.

scholarly journals The intracluster magnetic field in the double relic galaxy cluster Abell 2345

2021 ◽  
Vol 502 (2) ◽  
pp. 2518-2535
Author(s):  
C Stuardi ◽  
A Bonafede ◽  
L Lovisari ◽  
P Domínguez-Fernández ◽  
F Vazza ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Power Spectrum ◽  
Electron Density ◽  
Galaxy Clusters ◽  
Radial Profile ◽  
Electron Density Profile ◽  
Thermal Electron ◽  
X Ray ◽  
Radial Profiles

ABSTRACT Magnetic fields are ubiquitous in galaxy clusters, yet their radial profile, power spectrum, and connection to host cluster properties are poorly known. Merging galaxy clusters hosting diffuse polarized emission in the form of radio relics offer a unique possibility to study the magnetic fields in these complex systems. In this paper, we investigate the intracluster magnetic field in Abell 2345. This cluster hosts two radio relics that we detected in polarization with 1–2 GHz Jansky Very Large Array observations. X-ray XMM–Newton images show a very disturbed morphology. We derived the rotation measure (RM) of five polarized sources within ∼1 Mpc from the cluster centre applying the RM synthesis. Both, the average RM and the RM dispersion radial profiles probe the presence of intracluster magnetic fields. Using the thermal electron density profile derived from X-ray analysis and simulating a 3D magnetic field with fluctuations following a power spectrum derived from magneto-hydrodynamical cosmological simulations, we build mock RM images of the cluster. We constrained the magnetic field profile in the eastern radio relic sector by comparing simulated and observed RM images. We find that, within the framework of our model, the data require a magnetic field scaling with thermal electron density as B(r) ∝ ne(r). The best model has a central magnetic field (within a 200 kpc radius) of 2.8$\pm 0.1 \ \mu$G. The average magnetic field at the position of the eastern relic is $\sim 0.3 \ \mu$G, a factor 2.7 lower than the equipartition estimate.

X-ray wavelength survey of iron and nickel L-shell emission and resonance contributions to their intensities

2008 ◽  
Vol 86 (1) ◽  
pp. 191-198 ◽  
Author(s):  
M F Gu
Keyword(s):  
Electron Beam ◽  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Ion Traps ◽  
Laboratory Astrophysics ◽  
X Ray ◽  
The Past ◽  
Line Identification

As part of the laboratory astrophysics program at the electron beam ion traps of the Lawrence Livermore National Laboratory, L-shell X-ray emission of Fe and Ni ions have been studied extensively in the past decade. In this paper, we review these experimental efforts in line identification and wavelength surveys of Fe and Ni L-shell emission and resonance contributions to their intensities. PACS Nos.: 52.72.+v, 52.20.–j, 34.80.Kw

scholarly journals Spatially resolved spectra from a new x-ray imaging crystal spectrometer for measurements of ion and electron temperature profiles (invited)

2004 ◽  
Vol 75 (10) ◽  
pp. 3660-3665 ◽  
Author(s):  
M. Bitter ◽  
K. W. Hill ◽  
B. Stratton ◽  
A. L. Roquemore ◽  
D. Mastrovito ◽  
...  
Keyword(s):  
Electron Temperature ◽  
Temperature Profiles ◽  
Crystal Spectrometer ◽  
X Ray ◽  
Spatially Resolved ◽  
X Ray Imaging

New type of x-ray imaging intensifier

2002 ◽  
Author(s):  
Ye Li ◽  
Lichen Fu ◽  
Tangren Dan ◽  
Delong Jiang ◽  
Qingduo Duanmu ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Imaging ◽  
New Type
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