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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Gold L-shell emission spectroscopy as a temperature diagnostic in laser-driven experiments

Measurements of plasma conditions within gold hohlraums are challenging but provide important information about hohlraum energy transport. To date, there are no reliable passive diagnostic approaches that produce information about the hohlraum plasma conditions. Gold L-shell emission spectroscopy is a promising method to measure the electron temperature in multi-keV gold hohlraum plasmas. In this study, we compare time-resolved measurements of gold L-shell spectra against a more conventional electron temperature-sensitive diagnostic, K-shell emission from zinc, a mid-Z dopant. The Au L-shell and Zn K-shell spectra are taken simultaneously. The analysis of both sets of data exhibits good agreement with a singular rad-hydro model, suggesting a similar evolution in the mean electron temperature of the hohlraum plasma. These findings support the use of L-shell spectroscopy of gold as a method to study gold plasma conditions.

Emission spectroscopy↗
DOE OSTI2025

Demonstration of full-scale spatiotemporal diagnostics of solid-density plasmas driven by an ultra-short relativistic laser pulse using an X-ray free-electron laser

Understanding the complex plasma dynamics in ultra-intense relativistic laser–solid interactions is of fundamental importance for applications of laser–plasma-based particle accelerators, the creation of high-energy-density matter, understanding planetary science, and laser-driven fusion energy. However, experimental efforts in this regime have been limited by the lack of accessibility of over-critical densities and the poor spatiotemporal resolution of conventional diagnostics. Over the last decade, the advent of femtosecond brilliant hard X-ray free-electron lasers (XFELs) has opened new horizons to overcome these limitations. Here, for the first time, we present full-scale spatiotemporal measurements of solid-density plasma dynamics, including preplasma generation with tens of nanometer scale length driven by the leading edge of a relativistic laser pulse, ultrafast heating and ionization at the main pulse arrival, the laser-driven blast wave, and transient surface return current-induced compression dynamics up to hundreds of picoseconds after interaction. These observations are enabled by utilizing a novel combination of advanced X-ray diagnostics including small-angle X-ray scattering, resonant X-ray emission spectroscopy, and propagation-based X-ray phase-contrast imaging simultaneously at the European XFEL-HED beamline station.

Huang, Lingen [Helmholtz-Zentrum Dresden-Rossendor↗
DOE OSTI2025

Application of the portable diagnostic package to the Wisconsin high-temperature-superconducting axisymmetric mirror (WHAM)

We present an application of the Portable Diagnostic Package (PDP) on the Wisconsin High-temperature-superconducting Axisymmetric Mirror (WHAM), which integrates an optical emission spectroscopy (OES) system and an active Thomson scattering (TS) system. The OES system facilitates a comprehensive impurity line survey and enables flow measurements through the Doppler effect observed on impurity lines. Plasma rotation profiles were successfully derived from doubly charged carbon lines. The TS system enabled the first measurements of the electron temperature in commissioning plasmas on WHAM. Notably, the PDP was installed, commissioned, and used to obtain OES and TS data within ∼6 months from project start, enabled by its designed portability and standardized interfaces. These results demonstrate the PDP’s potential to accelerate diagnostic readiness and advance experimental plasma studies.

Doppler effect↗
DOE OSTI2026

Multi-diagnostic characterization of laser-produced tin plasmas for EUV lithography

We present a comprehensive characterization of laser-produced tin (Sn) plasmas relevant to extreme ultraviolet (EUV) lithography using a multi-diagnostic suite integrated into the new experimental platform, “SparkLight.” Tin plasmas are generated by irradiating a continuously moving tin-coated wire with laser pulses (1064 nm, 10 ns, up to 5.7 × 10 10 W/cm 2 ) and probed via coherent Thomson scattering, laser interferometry, and EUV emission spectroscopy. Thomson scattering measurements reveal electron temperatures and densities that decay with distance from the target. Densities derived from Thomson scattering are cross-validated against laser interferometry, showing excellent agreement. Correlating the results of these laser diagnostics with spatially resolved EUV spectroscopy suggests that the bulk of useful EUV emission originates within 150 μm of the target and is generated under suboptimal plasma conditions. This work demonstrates a practical integrated approach for plasma characterization in EUV source development.

Musikhin, S. [Princeton Plasma Physics Laboratory ↗
DOE OSTI2015

A wave model of refraction of laser beams with a discrete change in intensity in their cross section and their application for diagnostics of extended nonstationary phase objects

A beam model with a discrete change in the cross-sectional intensity is proposed to describe refraction of laser beams formed on the basis of diffractive optical elements. In calculating the wave field of the beams of this class under conditions of strong refraction, in contrast to the traditional asymptotics of geometric optics which assumes a transition to the infinite limits of integration and obtaining an analytical solution, it is proposed to calculate the integral in the vicinity of stationary points. This approach allows the development of a fast algorithm for correct calculation of the wave field of the laser beams that are employed in probing and diagnostics of extended optically inhomogeneous media. Examples of the algorithm application for diagnostics of extended nonstationary objects in liquid are presented. (laser beams)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Application of deep neural networks to improve diagnostic accuracy of rheumatoid arthritis using diffuse optical tomography

A set of deep neural network models for rheumatoid arthritis (RA) classification using a highway network, a convolutional neural network and a residual network is proposed based on the data of diffuse optical tomography (DOT) utilising near-infrared light, which ensures early diagnosis of pathophysiological changes resulting from inflammation. A numerical model of the finger is used to generate images to overcome the inherent problem of insufficient clinical DOT images available. The proposed deep neural network models are applied to automatically classify simulated DOT images of inflamed and non-inflamed joints and transfer learning is also used to improve the performance of the classification. The results demonstrate that all three deep neural network methods improve the diagnostic accuracy as compared to the widely applied support vector machine (SVM), especially for high inter-subject variability databases. In cases of distinct modelled severity of disease, residual network achieved the highest accuracy (> 99 %), and both of highway and convolutional neural networks reached 99 %, respectively. However, as the severity of the modelled disease is reduced, this accuracy is reduced to 75.2 % for residual networks. The results indicate that transfer learning can improve the performance of deep neural network methods on RA classification from DOT data and highlight their potential as a computer aided tool in DOT diagnostic systems. (paper)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Monte Carlo Analysis of the Performance of the ITER Diagnostic Residual Gas Analyzer

The composition of exhausted gas is a key parameter in long-pulse plasma fusion experiments, and its evolution shall be monitored at timescales relevant to plasma dynamics and plasma-wall interactions. A diagnostic residual gas analyzer (DRGA) is a multisensor instrument particularly suited to these studies, and ITER will adopt DRGAs in the equatorial and in the divertor tokamak regions. In this work, we have revisited the design of the ITER divertor DRGA through simple vacuum analytical considerations supported by simulations conducted with Molflow+, a test particle Monte Carlo (TPMC) simulation code commonly used in the particle accelerator community. Here, starting with recommendations on the manufacturing of the vacuum piping of the DRGA, this work is followed by a complete vacuum characterization of the diagnostic vacuum setup (pressure profiles at base pressure and during sampling, orifice diameter, and length optimization), and finally, the in-vessel residence time of the most important gas species is simulated. These studies have allowed us to give insights into some experimental results recently found on the prototype DRGA installed in the Wendelstein W7-X stellarator.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Comparing narrow- and broad-line AGNs in a new diagnostic diagram for emission-line galaxies based on WISE data

Using a new color–color diagnostic diagram in the mid-infrared (MIR) built from WISE data, the MIRDD, we compare narrow-emission-line galaxies (NELGs) that exhibit different activity types (star-forming galaxies (SFGs) and active galactic nuclei (AGNs), i.e., LINERs, Seyfert 2 galaxies (Sy2s), and Transition-type Objects (TOs)), as determined using one standard diagnostic diagram in the optical (BPT–VO), with broad-line AGNs (QSOs and Sy1s) and BL Lac objects at low redshift (z⩽0.25). We show that the BL Lac objects occupy the same region as the LINERs in the MIRDD, whereas the QSOs and Sy1s occupy an intermediate region between the LINERs and the Sy2s. In the MIRDD these galaxies trace a sequence that can be reproduced by a power law, F{sub ν}=ν{sup α}, where the spectral index, α, varies from 0 to −2, which is similar to what is observed in the optical/ultraviolet part of the spectra of AGNs with different luminosities. For the NELGs with different activity types, we perform a stellar-population synthesis analysis, confirming that their specific positions in the MIRD depend on their star formation histories (SFH) and demonstrating that the W2−W3 color is tightly correlated with the level of star formation in their host galaxies. In good agreement with the SFH analysis, a comparison of their MIR colors with the colors yielded by spectral energy distributions (SEDs) of galaxies with different activity types shows that the SED of the LINERs is similar to the SEDs of the QSOs and Sy1s, consistent with AGN galaxies with mild star formation, whereas the SEDs of the Sy2s and TOs are consistent with AGN galaxies with strong star formation components. For the BL Lac objects, we show that their blue MIR colors can only be fitted with an SED that has no star formation component, consistent with AGNs in elliptical-type galaxies. From their similarities in MIR colors and SEDs, we infer that, in the nearby universe, the level of star formation activity most probably increases in the host galaxies of emission-line galaxies with different activity types along the sequence BL Lac → LINER → QSO/Sy1 → Sy2 → TO → SFG.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

FAST STAR, SLOW STAR; OLD STAR, YOUNG STAR: SUBGIANT ROTATION AS A POPULATION AND STELLAR PHYSICS DIAGNOSTIC

Stellar rotation is a strong function of both mass and evolutionary state. Missions such as Kepler and CoRoT provide tens of thousands of rotation periods, drawn from stellar populations that contain objects at a range of masses, ages, and evolutionary states. Given a set of reasonable starting conditions and a prescription for angular momentum loss, we address the expected range of rotation periods for cool field stellar populations (∼0.4-2.0 M{sub ☉}). We find that cool stars fall into three distinct regimes in rotation. Rapid rotators with surface periods less than 10 days are either young low-mass main sequence (MS) stars, or higher mass subgiants which leave the MS with high rotation rates. Intermediate rotators (10-40 days) can be either cool MS dwarfs, suitable for gyrochronology, or crossing subgiants at a range of masses. Gyrochronology relations must therefore be applied cautiously, since there is an abundant population of subgiant contaminants. The slowest rotators, at periods greater than 40 days, are lower mass subgiants undergoing envelope expansion. We identify additional diagnostic uses of rotation periods. There exists a period-age relation for subgiants distinct from the MS period-age relations. There is also a period-radius relation that can be used as a constraint on the stellar radius, particularly in the interesting case of planet host stars. The high-mass/low-mass break in the rotation distribution on the MS persists onto the subgiant branch, and has potential as a diagnostic of stellar mass. Finally, this set of theoretical predictions can be compared to extensive datasets to motivate improved modeling.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

The diagnostic potential of Fe lines applied to protostellar jets

We investigate the diagnostic capabilities of iron lines for tracing the physical conditions of shock-excited gas in jets driven by pre-main sequence stars. We have analyzed the 3000-25000 Å, X-shooter spectra of two jets driven by the pre-main sequence stars ESO-Hα 574 and Par-Lup 3-4. Both spectra are very rich in [Fe II] lines over the whole spectral range; in addition, lines from [Fe III] are detected in the ESO-Hα 574 spectrum. Non-local thermal equilibrium codes solving the equations of the statistical equilibrium along with codes for the ionization equilibrium are used to derive the gas excitation conditions of electron temperature and density and fractional ionization. An estimate of the iron gas-phase abundance is provided by comparing the iron lines emissivity with that of neutral oxygen at 6300 Å. The [Fe II] line analysis indicates that the jet driven by ESO-Hα 574 is, on average, colder (T {sub e} ∼ 9000 K), less dense (n {sub e} ∼ 2 × 10{sup 4} cm{sup –3}), and more ionized (x {sub e} ∼ 0.7) than the Par-Lup 3-4 jet (T {sub e} ∼ 13,000 K, n {sub e} ∼ 6 × 10{sup 4} cm{sup –3}, x {sub e} < 0.4), even if the existence of a higher density component (n {sub e} ∼ 2 × 10{sup 5} cm{sup –3}) is probed by the [Fe III] and [Fe II] ultra-violet lines. The physical conditions derived from the iron lines are compared with shock models suggesting that the shock at work in ESO-Hα 574 is faster and likely more energetic than the Par-Lup 3-4 shock. This latter feature is confirmed by the high percentage of gas-phase iron measured in ESO-Hα 574 (50%-60% of its solar abundance in comparison with less than 30% in Par-Lup 3-4), which testifies that the ESO-Hα 574 shock is powerful enough to partially destroy the dust present inside the jet. This work demonstrates that a multiline Fe analysis can be effectively used to probe the excitation and ionization conditions of the gas in a jet without any assumption on ionic abundances. The main limitation on the diagnostics resides in the large uncertainties of the atomic data, which, however, can be overcome through a statistical approach involving many lines.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

[Ne III]/[O II] as an ionization parameter diagnostic in star-forming galaxies

We present our parameterizations of the log([Ne III]λ3869/[O II]λ3727) (Ne3O2) and log([O III]λ5007/[O II]λ3727) (O3O2) ratios as diagnostics of ionization parameter in star-forming galaxies. Our calibrations are based on the Starburst99/Mappings III photoionization models, which extend up to the extremely high values of ionization parameter found in high-redshift galaxies. While similar calibrations have been presented previously for O3O2, this is the first such calibration of Ne3O2. We illustrate the tight correlation between these two ratios for star-forming galaxies and discuss the underlying physics that dictates their very similar evolution. Based on this work, we propose the Ne3O2 ratio as a new and useful diagnostic of ionization parameter for star-forming galaxies. Given the Ne3O2 ratio's relative insensitivity to reddening, this ratio is particularly valuable for use with galaxies that have uncertain amounts of extinction. The short wavelengths of the Ne3O2 ratio can also be applied out to very high redshifts, extending studies of galaxies' ionization parameters out to z ∼ 1.6 with optical spectroscopy and z ∼ 5.2 with ground-based near-infrared spectra.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

CONTINUOUS MID-INFRARED STAR FORMATION RATE INDICATORS: DIAGNOSTICS FOR 0 < z < 3 STAR-FORMING GALAXIES

We present continuous, monochromatic star formation rate (SFR) indicators over the mid-infrared wavelength range of 6–70 μm. We use a sample of 58 star-forming galaxies (SFGs) in the Spitzer–SDSS–GALEX Spectroscopic Survey at z < 0.2, for which there is a rich suite of multi-wavelength photometry and spectroscopy from the ultraviolet through to the infrared. The data from the Spitzer Infrared Spectrograph (IRS) of these galaxies, which spans 5–40 μm, is anchored to their photometric counterparts. The spectral region between 40–70 μm is interpolated using dust model fits to the IRS spectrum and Spitzer 70 and 160 μm photometry. Since there are no sharp spectral features in this region, we expect these interpolations to be robust. This spectral range is calibrated as a SFR diagnostic using several reference SFR indicators to mitigate potential bias. Our band-specific continuous SFR indicators are found to be consistent with monochromatic calibrations in the local universe, as derived from Spitzer, WISE, and Herschel photometry. Our local composite template and continuous SFR diagnostics are made available for public use through the NASA/IPAC Infrared Science Archive (IRSA) and have typical dispersions of 30% or less. We discuss the validity and range of applicability for our SFR indicators in the context of unveiling the formation and evolution of galaxies. Additionally, in the era of the James Webb Space Telescope this will become a flexible tool, applicable to any SFG up to z ∼ 3.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

P-MaNGA: GRADIENTS IN RECENT STAR FORMATION HISTORIES AS DIAGNOSTICS FOR GALAXY GROWTH AND DEATH

We present an analysis of the data produced by the MaNGA prototype run (P-MaNGA), aiming to test how the radial gradients in recent star formation histories, as indicated by the 4000 Å break (D{sub n}(4000)), Hδ absorption (EW(Hδ{sub A})), and Hα emission (EW(Hα)) indices, can be useful for understanding disk growth and star formation cessation in local galaxies. We classify 12 galaxies observed on two P-MaNGA plates as either centrally quiescent (CQ) or centrally star-forming (CSF), according to whether D{sub n}(4000) measured in the central spaxel of each datacube exceeds 1.6. For each spaxel we generate both 2D maps and radial profiles of D{sub n}(4000), EW(Hδ{sub A}), and EW(Hα). We find that CSF galaxies generally show very weak or no radial variation in these diagnostics. In contrast, CQ galaxies present significant radial gradients, in the sense that D{sub n}(4000) decreases, while both EW(Hδ{sub A}) and EW(Hα) increase from the galactic center outward. The outer regions of the galaxies show greater scatter on diagrams relating the three parameters than their central parts. In particular, the clear separation between centrally measured quiescent and star-forming galaxies in these diagnostic planes is largely filled in by the outer parts of galaxies whose global colors place them in the green valley, supporting the idea that the green valley represents a transition between blue-cloud and red-sequence phases, at least in our small sample. These results are consistent with a picture in which the cessation of star formation propagates from the center of a galaxy outward as it moves to the red sequence.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2015

THE FORMATION OF IRIS DIAGNOSTICS. VIII. IRIS OBSERVATIONS IN THE C ii 133.5 nm MULTIPLET

The C ii 133.5 nm multiplet has been observed by NASA’s Interface Region Imaging Spectrograph (IRIS) in unprecedented spatial resolution. The aims of this work are to characterize these new observations of the C ii lines, place them in context with previous work, and to identify any additional value the C ii lines bring when compared with other spectral lines. We make use of wide, long exposure IRIS rasters covering the quiet Sun and an active region. Line properties such as velocity shift and width are extracted from individual spectra and analyzed. The lines have a variety of shapes (mostly single-peak or double-peak), are strongest in active regions and weaker in the quiet Sun. The ratio between the 133.4 and 133.5 nm components is always less than 1.8, indicating that their radiation is optically thick in all locations. Maps of the C ii line widths are a powerful new diagnostic of chromospheric structures, and their line shifts are a robust velocity diagnostic. Compared with earlier quiet Sun observations, we find similar absolute intensities and mean line widths, but smaller redshifts; this difference can perhaps be attributed to differences in spectral resolution and spatial coverage. The C ii intensity maps are somewhat similar to those of transition region lines, but also share some features with chromospheric maps such as those from the Mg ii k line, indicating that they are formed between the upper chromosphere and transition region. C ii intensity, width, and velocity maps can therefore be used to gather additional information about the upper chromosphere.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Validation of gyrokinetic simulations of a National Spherical Torus eXperiment H-mode plasma and comparisons with a high-k scattering synthetic diagnostic

A new extensive validation study performed for a modest-beta National Spherical Torus eXperiment (NSTX) neutral beam injection-heated H-mode discharge predicts that electron thermal transport can be entirely explained by short-wavelength electron-scale turbulence fluctuations driven by the electron temperature gradient mode (ETG), both in conditions of strong and weak ETG turbulence drive. Quantitative comparisons between high-k fluctuation measurements and simulations are performed via a novel synthetic high-k diagnostic. Computationally intensive electron-scale simulations featuring an unusually large domain (L r , L θ ) ~ (20, 20)ρ s are shown to be required for accurate deployment of the synthetic diagnostic. Ion thermal transport is shown to be close to neoclassical levels, consistent with stable ion-scale turbulence simulations conducted with the GYRO code. Electron-scale GYRO simulations are shown to match the thermal power-balance estimates from TRANSP. The frequency spectra characteristics of electron-scale turbulence (spectral peak and width) can be consistently reproduced by the synthetic spectra, but these reveal not to be a critical constraint on the simulation model. The shape of the high-k wavenumber spectrum and the fluctuation level ratio between the strong and weak ETG conditions can also be simultaneously matched by electron-scale simulations within sensitivity scans about the experimental profile values, and result to be great discriminators of the turbulence models analyzed. Together, electron thermal power comparisons and quantitative agreement of electron-scale turbulence spectra give strong evidence supporting electron-scale ETG fluctuations as the main mechanism driving anomalous electron thermal transport in the two outer-core conditions of the modest-beta NSTX H-mode analyzed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Wire, hybrid, and laser-cut X-pinches as Talbot–Lau backlighters for electron density diagnostics

Talbot–Lau x-ray deflectometry (TXD) enables refraction-based imaging for high-energy-density physics experiments, and thus, it has been studied and developed with the goal of diagnosing plasmas relevant to inertial confinement and magnetic liner inertial fusion. X-pinches, known for reliably generating fast (~1 ns), small (~1 µm) x-ray sources, were driven on the compact current driver generator for ablation structure and implosion studies (~200 kA, 150 ns) as a potential backlighter source for TXD. Considering that different X-pinch configurations have characteristic advantages and drawbacks as x-ray generating loads, three distinct copper X-pinch configurations were studied: the wire X-pinch, the hybrid X-pinch, and the laser-cut X-pinch. Furthermore, the Cu K-shell emission from each configuration was characterized and analyzed regarding the specific backlighter requirements for an 8 keV TXD system: spatial and temporal resolution, number of sources, time of emission, spectrum, and reproducibility. Recommendations for future experimental improvements and applications are presented. The electron density of static objects was retrieved from Moiré images obtained through TXD. This allowed to calculate the mass density of static samples within 4% of the expected value for laser-cut X-pinches, which were found to be the optimal X-pinch configuration for TXD due to their high reproducibility, small source size (≤5 µm), short duration (~1 ns), and up to 106 W peak power near 8 keV photon energy. Plasma loads were imaged through TXD for the first-time using laser-cut X-pinch backlighting. Experimental images were compared with simulations from the x-ray wave-front propagation code, demonstrating that TXD can be a powerful x-ray refraction-based diagnostic for dense Z-pinch loads. Future plans for Talbot–Lau interferometry diagnostics in the pulsed-power environment are described.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2026

Diagnostic x-ray source using electrons produced by a 100 J-class picosecond laser

Many laser-based high-energy-density science (HEDS) facilities have one or more short-pulse (sub- to few-picosecond) laser beams for diagnostics. For the past decade, we have been developing a novel x-ray probing capability using such picosecond lasers interacting with an underdense plasma to produce relativistic electrons. The ultimate goal of these experiments is to demonstrate a new type of x-ray backlighter using the short-pulse ARC laser at the National Ignition Facility (NIF). Before this diagnostic is fielded at the NIF, it is critical to demonstrate the viability and reproducibility of the x-ray source on comparable high-power short-pulse laser systems. We present experiments that were carried out with the OMEGA EP laser at the University of Rochester’s laboratory for laser energetics. In these experiments, high-energy electrons are produced through a combination of the self-modulation instability and direct laser acceleration in an underdense gas jet. These electrons generate directional x-rays with characteristic energies up to several tens of keV as they execute betatron motion in the ion channel, and the inverse Compton scattering process generates even harder x-rays, with characteristic photon energies of 60–240 keV. When implemented on the OMEGA EP laser(s), this x-ray source yields results that are comparable to those obtained recently on the short-pulse Titan laser at the Jupiter Laser Facility at Lawrence Livermore National Laboratory, after accounting for differences in laser energy, peak intensity, focusing f/#, and plasma source. Applications of such an x-ray source for HEDS experiments are discussed.

backlighter↗
DOE OSTI2019

The He/Ne beam diagnostic for line-ratio spectroscopy in the island divertor of Wendelstein 7-X

a versatile gas injection system and an absolute calibrated spectroscopic observation system with more than 200 lines-of-sight have been installed in two divertor locations in the Wendelstein 7-X stellarator. This powerful setup enables among other measurements to infer T e and n e in the divertor region by means of line-ratio spectroscopy on thermal helium. This is a robust and routinely used diagnostic at W7-X and this work describes its main characteristics and shows some examples of T e and n e profiles. In particular it is shown that the inclusion of high Rydberg states in the helium collisional-radiative model is necessary to obtain a realistic estimate of T e . The applicability of the diagnostic is currently being extended towards the low T e and high n e conditions occurring during detachment by means of line-ratio spectroscopy on neon. Initial T e , n e profiles obtained with a neon-beam are here presented.

47 OTHER INSTRUMENTATION↗