Impurity Line Emission Research Articles

Electron Temperature Measurements Using a Two-Filter Soft X-ray Array in VEST.

A multichannel soft X-ray (SXR) array has been developed to measure the electron temperature in the Versatile Experiment Spherical Torus (VEST). To estimate electron temperature using the two-filter method applied to SXR intensity, we designed a pinhole camera that has two photodiode arrays with different metallic filters. We also adopted a filter wheel and tested various filter parameters to find the optimal filter set. Through tests, the combination of aluminum and beryllium was found to be the most suitable for the current experimental conditions in VEST. The filtered SXR signals were acquired with a low-noise preamplifier, exhibiting sufficient signal-to-noise ratios for electron temperature estimation based on the intensity ratio of two signals obtained with different filters. The estimated electron temperature from the developed two-filter SXR array showed reasonably matched levels and consistent trends with Thomson scattering measurements. Error contribution from impurity line emission is also discussed.

Development of space-resolved EUV spectrometers working at 5–138 Å for profile observation of high-Z impurity ions in EAST plasma

In order to observe the radial profile of impurity line emission in a short wavelength range and to study the transport of metallic impurity ions intrinsically existing in plasma, two pairs of space-resolved extreme ultraviolet (EUV) spectrometers working at 5–138 Å were newly established on EAST tokamak. A back-illuminated complementary metal oxide semiconductor (CMOS) detector with a small pixel size of 6.5 × 6.5 μm2 and a varied-ling-spacing (VLS) concave holographic grating with a central density of 2400 grooves/mm allows the EUV spectrometers have good spectral resolution. A precise wavelength calibration is performed with cubic polynomial fitting using well-known emission lines from light impurity ions. The radial intensity profile of Cu XX at 12.570 Å and Cu XXI at 10.392 Å were observed successfully by space-resolved EUV spectrometers during H-mode discharge. The rapid change in the W XXXIII radial profile during the impurity burst period was clearly observed with sufficient intensity. The results show that the newly developed space-resolved EUV spectrometers have excellent performance in impurity diagnostics.

Performance improvement of space-resolved extreme ultraviolet spectrometer by use of complementary metal-oxide semiconductor detectors at the Experimental Advanced Superconducting Tokamak.

Two pairs of space-resolved extreme ultraviolet (EUV) spectrometers working at 5-138 Å with different vertical observation ranges of -7 ≤ Z ≤ 19 and -18 ≤ Z ≤ 8cm have been newly developed to observe the radial profile of impurity line emissions and to study the transport of high-Z impurity ions intrinsically existing in EAST tokamak plasmas. Both spectrometers are equipped with a complementary metal-oxide semiconductor (CMOS) detector (Andor Marana-X 4.2B-6, Oxford Instruments) with sensitive area of 13.3 × 13.3mm2 and number of pixels equal to 2048 × 2048 (6.5 × 6.5 µm2/pixels). Compared to the currently operating space-resolved EUV spectrometers with a charge-coupled detector (CCD: 1024 × 255 pixels, 26 × 26 µm2) working at 30-520 Å, this spectrometer's performance was substantially improved by using the CMOS detector. First, the spectral resolution measured at full width at half maximum was improved in the whole wavelength range, e.g., Δλ1/2_CMOS = 0.092 Å and Δλ1/2_CCD = 0.124 Å at C VI 33.73 Å and Δλ1/2_CMOS = 0.104 Å and Δλ1/2_CCD = 0.228 Å at Mo XXXI 115.999 Å, thus enabling a more accurate analysis of spectra with complicated structure such as tungsten unresolved transition array in the range 45-65 Å. Second, the temporal resolution was largely improved due to the high-speed data acquisition system of the CMOS detector, e.g., Δt_CMOS = 15 ms/frame and Δt_CCD = 200 ms/frame at routine operation in the radial profile measurement. Third, signal saturation issues that occurred when using the old CCD sensor during impurity accumulation now disappeared entirely using the CMOS detector due to lower exposure time at high readout rates, which largely improved the observation performance in similar impurity burst events. The above-mentioned performance improvements of the space-resolved EUV spectrometer led to a rapid change in the W XXXIII (52.22 Å) radial profile during a single cycle of low-frequency sawtooth oscillation with fst = 5-6Hz at a sufficient detector count rate.

Comparison of Doppler back-scattering and charge exchange measurements of E × B plasma rotation in the DIII-D tokamak under varying torque conditions

Measurements of the E × B toroidal angular velocity, ( is the radial electric field, B θ is the poloidal magnetic field), are made using the Doppler back-scattering (DBS) and charge-exchange recombination (CER) spectroscopy diagnostics. DBS uses the Doppler shift of wavenumber-resolved density fluctuations while CER uses the Doppler shift of impurity emission lines to independently measure plasma parameters for calculating the local radial electric field. DBS and CER profiles of as a function of normalized toroidal flux (ρ) are compared at various levels of neutral beam applied torque on the plasma. Under standard neoclassical theory is a flux surface quantity, making it appropriate to compare across diagnostics. DBS and CER generally show good agreement when comparing profiles at different levels of neutral beam injection-applied torque. Furthermore, the DBS values have close to the same precision as CER values when averaged over a similar time-scale and effects, such as prompt-torque are considered. DBS is able to observe the rapid (10 ms) modification of the profile by the diagnostic neutral beam ‘blips’. This modification is most pronounced when the blip applies a large relative change in torque on the plasma. Overall, these results could have implications on transport analysis and suggests using DBS and CER in conjunction to constrain values of the E × B-shear (sometimes called ).

A compact electron beam ion trap in support of high-temperature plasma diagnostics based on conduction-cooled superconducting coils.

Spectroscopic diagnostics of future fusion reactor plasmas require information on impurity line emissions, especially for relevant high-Z metal elements (e.g., tungsten). These materials will be widely used as plasma facing components for their high heat tolerance and low sputtering yield. Based on an electron beam ion trap, a compact impurity spectra platform is developed to mimic the high-temperature environment of a fusion reactor. The proposed platform can deliver a focused e-beam at energies over 30 keV using a confining magnetic field of ∼1.0T generated by two superconducting coils (NbTi). Cooled by a closed-loop cryocooler, the coils can avoid the usage of a complicated cryogenic system involving the handling of liquid helium. For spectroscopic studies of highly charged ions, a spherically curved crystal spectrometer is proposed to measure a wavelength range around 2-4 Å covering the typical wavelength range expected to be emitted by metal ions in a fusion plasma. This paper reports the design and development progress of the platform.

Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

Application of Bayesian tomography method to the visible spectroscopic diagnostic on HL-2A tokamak

As the commission of a visible spectroscopic diagnostic to the HL-2A tokamak for the measurements of both bremsstrahlung continuum radiation and impurity line emission, a Bayesian tomography method has been developed to this diagnostic for the reconstruction of a 2D emission distribution from line-integrated data. In this method, Gaussian process prior is adopted as an effective way to regularize the smoothness of the emission field, which can be truncated to enforce non-negative constraint of the emission values. For the reliability and quality assessment, uncertainty of the reconstruction can be examined through its confidence interval derived from a posterior probability. Performance of this Gaussian processtomography method is exemplified by the reconstructions of the bremsstrahlung continuum emission, which coincide with the equilibrium magnetic flux surfaces with respect to position and shape. In another case the reconstruction of CVI line emission in the visible range (n = 8→7, 529.05 nm) disclose the existence of a bright radiation belt due to the plasma–wall interaction.

Metallic impurity content behavior during ICRH-heated L-mode discharges in EAST

This study uses the diversity of materials at known locations in the experimental advanced superconducting tokamak to extract, local information on which plasma-surface interaction processes are dominant during ion cyclotron resonance heating (ICRH) (near vs far field effects). Metallic impurity content is indicated by the intensity of impurity line emissions observed with a fast-time-response extreme ultraviolet spectrometer, normalized to line-averaged plasma density, i.e. Iimp/ne. Parametric dependencies are explored over scans of ICRH and LH (lower hybrid) power and for different toroidal phasings between straps, strap power balance, and magnetic configurations. This diversity of behavior is interpreted as the signature of different physical processes. Before 2017, as only the upper divertor region contained tungsten (W), the W content in the core used to increase a lot when moving from lower to upper single null configurations, and was correlated with the total injected power rather than the ICRH power. Molybdenum, covering the part of the inner wall facing one ion cyclotron range of frequencies (ICRF) antenna appear sensitive to this antenna power and phasing benchmarked by modeling suggesting a probable interaction due to residual ICRF waves crossing the plasma. Materials close and magnetically-connected to an active antenna show better correlation with ICRF antenna electrical tuning than those which are far away, or not connected. This is particularly the case with W since 2018, because the limiter tiles of the LH launchers were changed from graphite to tungsten. In these latter conditions, it is shown that W sources at the mid-plane (equatorial plane) contribute to a significant fraction of the core contamination by tungsten (25% in ohmic regime, and more during ICRH).

Space-resolved extreme ultraviolet spectrometer for impurity diagnostics in HL-2A

Abstract A space-resolved extreme ultraviolet (EUV) spectrometer system has been developed in the HL-2A tokamak for impurity monitoring and transport studies. A charge-coupled-device (CCD) detector is mounted on a two-stage wavelength scanning mechanism for measuring the spatial profile of impurity line emissions in the wavelength range of 30−600 A. A good spatial profile of impurity line emissions is observed throughout the lower half of the HL-2A plasma along the vertical direction by installing a space-resolved slit in front of an entrance slit. The vertical observation range is ∼43 cm covering a wide plasma area from the plasma central region to the vicinity of divertor separatrix X-point. In order to make a critical analysis of the impurity transport, in particular, in the plasma edge, an accurate position calibration in the observed vertical impurity line intensity profile is necessary. For the purpose a thin metal bar is installed at the diagnositc port. Then, the vertical position of the impurity profile can be accurately determined throughout the entire wavelength range. Based on the present method, the local emissivity profile of impurity line emissions is well reconstructed with good accuracy through Abel inversion technique. Resultant CIV and CVI local emissivity profiles show a clear difference in the carbon transport between ohmic and NBI heating phases.

Development of vacuum ultraviolet spectroscopy for measuring edge impurity emission in the EAST tokamak

The dominant wavelength range of edge impurity emissions moves from the visible range to the vacuum ultraviolet (VUV) range, as heating power increasing in the Experimental Advanced Superconducting Tokamak (EAST). The measurement provided by the existing visible spectroscopies in EAST is not sufficient for impurity transport studies for high-parameters plasmas. Therefore, in this study, a VUV spectroscopy is newly developed to measure edge impurity emissions in EAST. One Seya-Namioka VUV spectrometer (McPherson 234/302) is used in the system, equipped with a concave-corrected holographic grating with groove density of 600 grooves mm–1. Impurity line emissions can be observed in the wavelength range of λ = 50–700 nm, covering VUV, near ultraviolet and visible ranges. The observed vertical range is Z = −350–350 mm. The minimum sampling time can be set to 5 ms under full vertical binning (FVB) mode. VUV spectroscopy has been used to measure the edge impurity emission for the 2019 EAST experimental campaign. Impurity spectra are identified for several impurity species, i.e., lithium (Li), carbon (C), oxygen (O), and iron (Fe). Several candidates for tungsten (W) lines are also measured but their clear identification is very difficult due to a strong overlap with Fe lines. Time evolutions of impurity carbon emissions of CII at 134.5 nm and CIII at 97.7 nm are analyzed to prove the system capability of time-resolved measurement. The measurements of the VUV spectroscopy are very helpful for edge impurity transport study in the high-parameters plasma in EAST.

Local profiles of line emission of impurity ions in rotating fusion plasmas

We analyze the poloidal distribution of impurity ions, such as C V, C VI and O VIII, in fast rotating KSTAR plasmas using the impurity emission lines in the 1–7 nm wavelength range obtained from the space-resolved extreme ultra violet spectrometer. This is aided particularly by a new tomographic reconstruction technique with limited viewing angles. The vacuum and extreme ultraviolet spectrometer system at ITER and its prototypes installed at KSTAR are one of the main diagnostic systems to monitor the impurity species in fusion plasmas; however, they have an insufficient field of view to utilize the conventional reconstruction method. The new algorithm developed in this work considers a curvilinear grid of pixels mapped onto the magnetic equilibrium and a weight factor considering toroidal rotational effect on impurity species. Validation tests with poloidally asymmetric images of synthetic plasma demonstrate that this method is highly useful for emission diagnostics that have a narrow field of view. The experimental results of the spatially resolved spectra from KSTAR plasma clearly show that even the light impurities such as carbon and oxygen are significantly affected by the toroidal rotation. Accordingly, the method is expected to be utilized for estimating the poloidal density profile of each charge state of an impurity species, which will play a key role in impurity transport studies.

Feasibility study for an edge main ion charge exchange recombination spectroscopy system at ASDEX Upgrade

A feasibility study for a new edge main ion charge exchange recombination spectroscopy (CXRS) system at the ASDEX Upgrade tokamak has been carried out. This diagnostic uses the new edge fast-ion Dα (FIDA) spectrometers and the optical heads of the existing edge CXRS systems. Standard CXRS resolved temperature and rotation profiles rely on the observation of impurity emission lines. The complexity of the photoemission processes and the fact that the measured ions represent the majority bulk plasma ions (here deuterium) make the interpretation of the main ion spectra in comparison more challenging. At the plasma edge, the diagnostic capabilities in terms of temporal and spatial resolution are extremely demanding. The difficulties in the interpretation of the main ion spectra are overcome by comprehensive fitting and forward modelling of the beam halo (which introduces a major challenge) using a collisional radiative model, as described in [1]. In this work, the diagnostic set up and the sensitivity of the main ion spectra to changes in plasma parameters have been characterized. The tools and techniques necessary for a correct interpretation of the spectra are also discussed. In addition to the halo effect, corrections due to atomic physics effects which could affect the splitting and broadening of the spectral Dα line and lead to misinterpretation of the spectra are evaluated. The first measurements of the edge main ion diagnostic are also presented.

A space-resolved extreme ultraviolet spectrometer for radial profile measurement of tungsten ions in the Experimental Advanced Superconducting Tokamak

In order to study the radial transport of tungsten ions in long-pulse H-mode discharges, a space-resolved spectrometer working at 30–520 Å has been newly developed to measure a radial profile of the tungsten line emission. The spectrometer is installed behind a long extension vacuum tube connected to a horizontal midplane diagnostic port of EAST tokamak. The long distance between the plasma and spectrometer, 8835.5 mm, enables observation of the radial profile of impurity line emissions in a wide vertical range of −8.5≤Z≤ 40 cm (−0.1≤ρ≤0.6). A good spectral resolution of Δλ0=4−5 pixels at the foot position of spectral line profiles and a high spatial resolution of ΔZ=2.5 cm are obtained in addition to a sufficient temporal resolution, e.g. 50 ms/frame. As a result, accurate radial profiles have been successfully obtained in EAST Ohmic and H-mode discharges for several impurity species such as carbon, oxygen, argon, iron and tungsten. The radial profiles of tungsten line emissions from W42+ – W45+ ions with 4p–4s transitions measured at two wavelength ranges of 45–70 Å and 120–140 Å are analyzed for the ion density evaluation based on the photon emissivity coefficient from ADAS database. The result shows that the density of W43+ – W45+ ions ranges at 2–6 × 108 cm−3 in steady H-mode discharges with Te(0)=3 keV and ne(0)=4 × 1013 cm−3.

Development of a Z eff diagnostic using visible and near-infrared bremsstrahlung light for the C-2W field-reversed configuration plasma.

In C-2W, an elevated impurity concentration can lead to significant degradation of plasma performance and energy losses through radiation. To gauge plasma contamination from impurities, the effective ion charge (Z eff) can be determined from measurements of bremsstrahlung continuum radiation over a small spectral range free from line radiation. To this end, a diagnostic system including visible and near-infrared bremsstrahlung detectors was deployed in C-2W to measure time-dependent radial distributions of Z eff. The system is complemented by an array of survey spectrometers which enable full-range spectroscopic measurements of impurity emission lines from the vacuum ultraviolet to the near infrared, providing a good picture of the plasma composition. Here, the design scheme for this integrated diagnostic system is presented and discussed.

Effect of neutron and -ray on charge-coupled device for vacuum/extreme ultraviolet spectroscopy in deuterium discharges of large helical device.

A charge-coupled device (CCD) is widely used as a detector of vacuum spectrometers in fusion devices. Recently, a deuterium plasma experiment has been initiated in a Large Helical Device (LHD). Totally 3.7 × 1018 neutrons have been yielded with energies of 2.45 MeV (D-D) and 14.1 MeV (D-T) during the deuterium experiment over four months. Meanwhile, γ-rays are radiated from plasma facing components and laboratory structural materials in a wide energy range, i.e., 0.01-12.0 MeV, through the neutron capture. It is well known that these neutrons and γ-rays bring serious problems to the CCD system. Then, several CCDs of vacuum ultraviolet/extreme ultraviolet/X-ray spectrometers installed at different locations on LHD for measurements of spectra and spatial profiles of impurity emission lines are examined to study the effect of neutrons and γ-rays. An additional CCD placed in a special shielding box made of 10 cm thick polyethylene contained 10% boron and 1.5 cm thick lead is also used for the detailed analysis. As a result, it is found that the CCD has no damage in the present neutron yield of LHD, while the background noise integrated for all pixels of CCD largely increases, i.e., 1-3 × 108 counts/s. The data analysis of CCD in the shielding box shows that the background noise caused by the γ-ray is smaller than that caused by the neutron, i.e., 41% from γ-rays and 59% from neutrons. It is also found that the noise can be partly removed by an accumulation of CCD frames or software programming.

High-speed VUV spectroscopy for edge impurity line emission measurements in HL-2A tokamak

A 20 cm focal length normal incidence vacuum ultraviolet (VUV_20 cm) monochromator with a fast time response has been developed for measuring edge impurity line emission in the wavelength range of 300–2000 Å on an HL-2A tokamak. An aberration corrected concave holographic grating with 1200 grooves/mm is adopted in the monochromator, which provides a wavelength dispersion of 40 Å mm−1. The aperture is f/4.5. A channel electron multiplier is used as a detector. The time resolution of the system is 17 μs. Wavelength calibration of the system has been done by using a hollow cathode light source in the laboratory with helium and argon gases. The obtained signals of helium and argon spectra are very strong since the inner surface of the monochromator vacuum chamber is blackened and the stray light level is then significantly reduced. The optical property of the system has been examined by scanning the width of the entrance and exit slits. The system is then installed at the mid-port of the HL-2A tokamak and typical line emissions from the HL-2A plasma are measured. Time behaviors of edge impurity line emissions are observed with the fast time response system in different plasma confinement regimes, especially in the H-mode discharges. The result shows that the VUV_20 cm system works very well to measure the edge impurity line emissions in the edge localized modes phase of H-mode discharges.

Effect of impurity source locations on up-down asymmetry in impurity distributions in the ergodic layer of large helical device

A space-resolved spectroscopy using a 3m normal incidence vacuum ultraviolet (VUV) spectrometer was developed to measure the VUV emission profiles in wavelength range of 300–3200Å from impurities in the edge plasmas in Large Helical Device (LHD). The edge plasma of the LHD is characterized by stochastic magnetic fields with three-dimensional structure intrinsically formed by helical coils called the “ergodic layer”. The VUV spectroscopy has revealed that intensity profiles of the impurity emission from the ergodic layer have strong up-down asymmetries, namely, the emission intensities are quite different between top and bottom plasma edges. Observations of the up-down asymmetries are summarized on the following impurity line emissions: (1) CII 1335.71Å (2s-2p), CIII 977.02Å (2s-2p), and CIV 1548.20Å (2s-2p) from intrinsic carbon impurity ions sputtered from the carbon divertor plates, (2) NeVII 465.22Å (2s-2p), NeVIII 770.41Å (2s-2p), ArVII 585.75Å (3s-3p), and ArVIII 700.24Å (3s-3p) from Ne or Ar ions introduced in plasmas by gas puffing, and (3) WVI 639.68Å (5d-6p) from W ions introduced in plasmas by pellet injection.

Space-resolved visible spectroscopy for two-dimensional measurement of hydrogen and impurity emission spectra and of plasma flow in the edge stochastic layer of LHD.

A space-resolved visible spectrometer system has been developed for two-dimensional (2D) distribution measurements of hydrogen and impurity emission spectra and of plasma flow in the edge stochastic layer of Large Helical Device (LHD). Astigmatism of the spectrometer has been suppressed by introducing additional toroidal and spherical mirrors. A good focal image at the exit slit is realized in a wide wavelength range (75 nm) as well as in a wide slit height direction (26 mm) with a 300 grooves/mm grating. The capability of the spectrometer optical system for the 2D measurement and further possible improvements are discussed in detail. An optical fiber array of 130 channels with a lens unit is used to spatially resolve the edge plasma into different magnetic field structure components: divertor strike points, divertor legs, X-point of the legs, the stochastic layer, and the last closed flux surface. With a 300 grooves/mm grating, the 2D distributions of several hydrogen and impurity line emissions are simultaneously obtained with absolute intensities. A clear correlation is obtained between the magnetic field structure and the emission intensity. With a 2400 grooves/mm grating with a good spectral resolution (0.03 nm/pixel), the 2D distributions of impurity flow velocity are obtained from the Doppler shift measurement. The wavelength position is accurately calibrated by investigating the wavelength dispersion as well as by correcting a mechanical error of the optical setting in the spectrometer. The uncertainty in the velocity is reduced to less than 10% of a typical impurity velocity ∼104 m/s. A temporal change in the flow directions is observed at different spatial locations in divertor detachment plasma.

Development of Multichannel Ion Doppler Spectroscopic System by Using Fast Camera

SUMMARYThe multichannel ion Doppler spectroscopic (M‐IDS) system using a fast camera as detectors has been newly developed to measure the spatial profiles of impurity spectral line emissions from plasmas. The M‐IDS system developed with eight viewing chords is characterized by the simplest optical systems, a fast sampling frequency, high number of shooting, and a low crosstalk of 3.5% on each chord. In order to verify the usefulness and reliability of the M‐IDS system, we have applied it for the start‐up plasma produced in the helicity injected spherical torus device. Resultantly, we have successfully measured the radial profiles of Doppler ion temperature Ti.D and Doppler ion velocity vi.D of the plasma with a good Gaussian fitting. However, we have found that the sampling frequency is upper limited by 25 kHz because the signal detected with a faster frequency from the CIII impurity line emission is too weak to be analyzed, and thus the sensitivity of the total system needs to be improved.

Radial magnetic compression in the expelled jet of a plasma deflagration accelerator

A spectroscopic study of a pulsed plasma deflagration accelerator is carried out that confirms the existence of a strong compression in the emerging jet at the exit plane of the device. An imaging spectrometer is used to collect broadened Hα emission from a transaxial slice of the emerging jet at high spatial resolution, and the radial plasma density profile is computed from Voigt fits of the Abel inverted emissivity profiles. The plasma temperature, determined via Doppler broadening of impurity line emission, is compared against the temperature predictions of a radial magnetohydrodynamic equilibrium model applied to the measured density profiles. Empirical scaling laws developed for the plasma density, combined with the measured and predicted temperatures, indicate that a radially equilibrated Z-pinch is formed within the expelled plasma jet at the exit plane during the deflagration process.