Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

International Nuclear Information System (INIS)

Gounder, J.D.; Kutne, P.; Meier, W.

2012-01-01

The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 °C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 °C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled laboratory

Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

Energy Technology Data Exchange (ETDEWEB)

Gounder, J.D., E-mail: James.Gounder@dlr.de; Kutne, P.; Meier, W.

2012-08-15

The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 Degree-Sign C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 Degree-Sign C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled

Helicon plasma ion temperature measurements and observed ion cyclotron heating in proto-MPEX

Science.gov (United States)

Beers, C. J.; Goulding, R. H.; Isler, R. C.; Martin, E. H.; Biewer, T. M.; Caneses, J. F.; Caughman, J. B. O.; Kafle, N.; Rapp, J.

2018-01-01

The Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) linear plasma device is a test bed for exploring and developing plasma source concepts to be employed in the future steady-state linear device Material Plasma Exposure eXperiment (MPEX) that will study plasma-material interactions for the nuclear fusion program. The concept foresees using a helicon plasma source supplemented with electron and ion heating systems to reach necessary plasma conditions. In this paper, we discuss ion temperature measurements obtained from Doppler broadening of spectral lines from argon ion test particles. Plasmas produced with helicon heating alone have average ion temperatures downstream of the Helicon antenna in the range of 3 ± 1 eV; ion temperature increases to 10 ± 3 eV are observed with the addition of ion cyclotron heating (ICH). The temperatures are higher at the edge than the center of the plasma either with or without ICH. This type of profile is observed with electrons as well. A one-dimensional RF antenna model is used to show where heating of the plasma is expected.

Electron temperature measurements in lowdensity plasmas by helium spectroscopy

International Nuclear Information System (INIS)

Brenning, N.

1977-09-01

This method to use relative intensities of singlet and triplet lines of neutral helium to measure electron temperature in low-density plasmas is examined. Calculations from measured and theoretical data about transitions in neutral helium are carried out and compared to experimental results. It is found that relative intensities of singlet and triplet lines from neutral helium only can be used for TE determination in low-density, short-duration plasmas. The most important limiting processes are excitation from the metastable 2 3 S level and excitation transfer in collisions between electrons and excited helium atoms. An evaluation method is suggested, which minimizes the effect of these processes. (author)

Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster

International Nuclear Information System (INIS)

Zhang, Zun; Tang, Haibin; Kong, Mengdi; Zhang, Zhe; Ren, Junxue

2015-01-01

Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3

Spectroscopic measurements of the density and electronic temperature at the plasma edge in Tore Supra

International Nuclear Information System (INIS)

Lediankine, A.

1996-01-01

The profiles of temperature and electronic density at the plasma edge are important to study the wall-plasma interaction and the radiative layers in the Tokamak plasmas. The laser ablation technique of the lithium allows to measure the profile of electronic density. To measure the profile of temperature, it has been used for the first time, the injection of a fluorine neutral atoms beam. The experiments, the results are described in this work. (N.C.)

Electron temperature measurements by the plasma line technique at the French incoherent scatter radar facilities

International Nuclear Information System (INIS)

Kofman, W.; Lejeune, G.; Hagfors, T.; Bauer, P.

1981-01-01

The results of experiments aimed at the determination of the electron temperature by a plasma line technique are presented. Using the multistatic capabilities of the French incoherent scatter radar, the plasma line frequencies were simultaneously measured at two receiving stations (Mende and Nancay) at the altitude corresponding to the maximum of the F layer. Different plasma line frequencies are measued because of different effective k vectors that appear in the thermal term of the plasma dispersion relation. We derive and apply two data analysis procedures that enable us to determine this frequency difference. Comparison of this measured frequency difference to that calculated using the ion component electron temperature demonstrates that the plasma lines could indeed be used to determine the electron temperature. A strong dependence of the power in the plasma line as a function of the angle between k vector and magnetic field is observed in agreement with the theory. The future developments of this technique with the EISCAT radar facilities are discussed

2D surface temperature measurement of plasma facing components with modulated active pyrometry

International Nuclear Information System (INIS)

Amiel, S.; Loarer, T.; Pocheau, C.; Roche, H.; Gauthier, E.; Aumeunier, M.-H.; Courtois, X.; Jouve, M.; Balorin, C.; Moncada, V.; Le Niliot, C.; Rigollet, F.

2014-01-01

In nuclear fusion devices, such as Tore Supra, the plasma facing components (PFC) are in carbon. Such components are exposed to very high heat flux and the surface temperature measurement is mandatory for the safety of the device and also for efficient plasma scenario development. Besides this measurement is essential to evaluate these heat fluxes for a better knowledge of the physics of plasma-wall interaction, it is also required to monitor the fatigue of PFCs. Infrared system (IR) is used to manage to measure surface temperature in real time. For carbon PFCs, the emissivity is high and known (ε ∼ 0.8), therefore the contribution of the reflected flux from environment and collected by the IR cameras can be neglected. However, the future tokamaks such as WEST and ITER will be equipped with PFCs in metal (W and Be/W, respectively) with low and variable emissivities (ε ∼ 0.1–0.4). Consequently, the reflected flux will contribute significantly in the collected flux by IR camera. The modulated active pyrometry, using a bicolor camera, proposed in this paper allows a 2D surface temperature measurement independently of the reflected fluxes and the emissivity. Experimental results with Tungsten sample are reported and compared with simultaneous measurement performed with classical pyrometry (monochromatic and bichromatic) with and without reflective flux demonstrating the efficiency of this method for surface temperature measurement independently of the reflected flux and the emissivity

Measurement of plasma potential and electron temperature by ball-pen probes in RFX-MOD

International Nuclear Information System (INIS)

Brotankova, J.; Adamek, J.; Stockel, J.; Martines, E.; Spolaore, M.; Cavazzana, R.; Serianni, G.; Vianello, N.; Zuin, M.

2009-01-01

The ball-pen probe (BPP) is an innovative electric probe for direct measurements of the plasma potential. This probe was developed in IPP Prague and it is based on the Katsumata probe concept. Combined measurements of the plasma potential by a BPP and floating potential by a Langmuir probe provide also the value of the electron temperature. First test of the BPP on the RFX-mod reversed field pinch in Padova has been performed in November 2006. The BPP head, made of boron nitride, is equipped with four graphite collectors, which are positioned at four different radial positions h inside four shafts hollow into the probe head. The radial profile of the plasma potential and also the electron temperature were measured

Interpretation of fast measurements of plasma potential, temperature and density in SOL of ASDEX Upgrade

DEFF Research Database (Denmark)

Horacek, J.; Adamek, J.; Müller, H.W.

2010-01-01

This paper focuses on interpretation of fast (1 µs) and local (2–4 mm) measurements of plasma density, potential and electron temperature in the edge plasma of tokamak ASDEX Upgrade. Steady-state radial profiles demonstrate the credibility of the ball-pen probe. We demonstrate that floating...... potential fluctuations measured by a Langmuir probe are dominated by plasma electron temperature rather than potential. Spatial and temporal scales are found consistent with expectations based on interchange-driven turbulence. Conditionally averaged signals found for both potential and density are also...

Surface temperature measurement of plasma facing components in tokamaks

International Nuclear Information System (INIS)

Amiel, Stephane

2014-01-01

During this PhD, the challenges on the non-intrusive surface temperature measurements of metallic plasma facing components in tokamaks are reported. Indeed, a precise material emissivity value is needed for classical infrared methods and the environment contribution has to be known particularly for low emissivities materials. Although methods have been developed to overcome these issues, they have been implemented solely for dedicated experiments. In any case, none of these methods are suitable for surface temperature measurement in tokamaks.The active pyrometry introduced in this study allows surface temperature measurements independently of reflected flux and emissivities using pulsed and modulated photothermal effect. This method has been validated in laboratory on metallic materials with reflected fluxes for pulsed and modulated modes. This experimental validation is coupled with a surface temperature variation induced by photothermal effect and temporal signal evolvement modelling in order to optimize both the heating source characteristics and the data acquisition and treatment. The experimental results have been used to determine the application range in temperature and detection wavelengths. In this context, the design of an active pyrometry system on tokamak has been completed, based on a bicolor camera for a thermography application in metallic (or low emissivity) environment.The active pyrometry method introduced in this study is a complementary technique of classical infrared methods used for thermography in tokamak environment which allows performing local and 2D surface temperature measurements independently of reflected fluxes and emissivities. (author) [fr

Measurement of excitation, ionization, and electron temperatures and positive ion concentrations in a 144 MHz inductively coupled radiofrequency plasma

International Nuclear Information System (INIS)

Walters, P.E.; Chester, T.L.; Winefordner, J.D.

1977-01-01

Diagnostic measurements of 144 MHz radiofrequency inductively coupled plasmas at pressures between 0.5 and 14 Torr have been made. Other variables studied included the gas type (Ar or Ne) and material in plasma (Ti or Tl). Parameters measured included excitation temperatures via the atomic Boltzmann plot and the two-line method, ionization electric probes. Excitation temperatures increased as the pressure of Ar or Ne plasmas decreased and reached a maximum of approx.9000 degreeK in the latter case and approx.6700 degreeK in the former case; Tl in the Ar plasma resulted in in a smaller rate of decrease of excitation temperature with increase of pressure of Ar. The ionization temperatures were lower than the excitation temperatures and were similar for both the Ar and Ne plasmas. Electron temperatures were about 10 times higher than the excitation temperatures indicating non-LTE behavior. Again, the electron temperatures indicating in Ne were considerably higher than in Ar. With the presence of metals, the electron temperatures with a metal in the Ar plasma were higher than in the absence. Positive ion concentrations were also measured for the various plasmas and were found to be similar (approx.10 18 m -3 ) in both the Ar and Ne plasmas. The presence of metals caused significant increase in the positive ion concentrations. From the results obtained, the optimum Ar pressure for Tl electrodeless discharge lamps operated at 144 MHz would be between 2 and 4 Torr

Measurements of ion temperature and flow of pulsed plasmas produced by a magnetized coaxial plasma gun device using an ion Doppler spectrometer

Science.gov (United States)

Kitagawa, Y.; Sakuma, I.; Iwamoto, D.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.

2012-10-01

It is important to know surface damage characteristics of plasma-facing component materials during transient heat and particle loads such as type I ELMs. A magnetized coaxial plasma gun (MCPG) device has been used as transient heat and particle source in ELM simulation experiments. Characteristics of pulsed plasmas produced by the MCPG device play an important role for the plasma material interaction. In this study, ion temperature and flow velocity of pulsed He plasmas were measured by an ion Doppler spectrometer (IDS). The IDS system consists of a light collection system including optical fibers, 1m-spectrometer and a 16 channel photomultiplier tube (PMT) detector. The IDS system measures the width and Doppler shift of HeII (468.58 nm) emission line with the time resolution of 1 μs. The Doppler broadened and shifted spectra were measured with 45 and 135 degree angles with respect to the plasmoid traveling direction. The observed emission line profile was represented by sum of two Gaussian components to determine the temperature and flow velocity. The minor component at around the wavelength of zero-velocity was produced by the stationary plasma. As the results, the ion velocity and temperature were 68 km/s and 19 eV, respectively. Thus, the He ion flow energy is 97 eV. The observed flow velocity agrees with that measured by a time of flight technique.

The influence of storage time and temperature on the measurement of serum, plasma and urine osmolality.

Science.gov (United States)

Bezuidenhout, Karla; Rensburg, Megan A; Hudson, Careen L; Essack, Younus; Davids, M Razeen

2016-07-01

Many clinical laboratories require that specimens for serum and urine osmolality determination be processed within 3 h of sampling or need to arrive at the laboratory on ice. This protocol is based on the World Health Organization report on sample storage and stability, but the recommendation lacks good supporting data. We studied the effect of storage temperature and time on osmolality measurements. Blood and urine samples were obtained from 16 patients and 25 healthy volunteers. Baseline serum, plasma and urine osmolality measurements were performed within 30 min. Measurements were then made at 3, 6, 12, 24 and 36 h on samples stored at 4-8℃ and room temperature. We compared baseline values with subsequent measurements and used difference plots to illustrate changes in osmolality. At 4-8℃, serum and plasma osmolality were stable for up to 36 h. At room temperature, serum and plasma osmolality were very stable for up to 12 h. At 24 and 36 h, changes from baseline osmolality were statistically significant and exceeded the total allowable error of 1.5% but not the reference change value of 4.1%. Urine osmolality was extremely stable at room temperature with a mean change of less than 1 mosmol/kg at 36 h. Serum and plasma samples can be stored at room temperature for up to 36 h before measuring osmolality. Cooling samples to 4-8℃ may be useful when delays in measurement beyond 12 h are anticipated. Urine osmolality is extremely stable for up to 36 h at room temperature. © The Author(s) 2015.

Helium temperature measurements in a hot filament magnetic mirror plasma using high resolution Doppler spectroscopy

Science.gov (United States)

Knott, S.; McCarthy, P. J.; Ruth, A. A.

2016-09-01

Langmuir probe and spectroscopic diagnostics are used to routinely measure electron temperature and density over a wide operating range in a reconfigured Double Plasma device at University College Cork, Ireland. The helium plasma, generated through thermionic emission from a negatively biased tungsten filament, is confined by an axisymmetric magnetic mirror configuration using two stacks of NdFeB permanent magnets, each of length 20 cm and diameter 3 cm placed just outside the 15 mm water cooling jacket enclosing a cylindrical vacuum vessel of internal diameter 25 cm. Plasma light is analysed using a Fourier Transform-type Bruker spectrometer with a highest achievable resolution of 0.08 cm-1 . In the present work, the conventional assumption of room temperature ions in the analysis of Langmuir probe data from low temperature plasmas is examined critically using Doppler spectroscopy of the 468.6 nm He II line. Results for ion temperatures obtained from spectroscopic data for a variety of engineering parameters (discharge voltage, gas pressure and plasma current) will be presented.

Measurement of ion temperature and flow in RF start-up plasmas in TST-2 and LATE

International Nuclear Information System (INIS)

Tsuda, Shintaro; Ejiri, Akira; Takase, Yuichi; Tsujii, Naoto; Takeuchi, Toshihiro; Tanaka, Hitoshi; Uchida, Masaki; Maekawa, Takashi

2015-01-01

The ion temperature and flow of RF start-up plasmas in TST-2 and LATE were measured using a visible spectrometer. The plasma currents were 9 kA and 8 kA, respectively. The typical ion temperatures T i and toroidal flow V ϕ were 4 eV and 1 km/s, respectively, in the TST-2 plasma sustained by the lower hybrid wave (20 kW) and T i ∼ 10 eV and V ϕ ∼ 5 km/s in the LATE plasma sustained by the electron cyclotron wave (50 kW). The poloidal flow velocities were comparable to the toroidal velocities. The ion temperatures were relatively high and the ion orbit loss can be significant. (author)

Fast-scanning heterodyne receiver for measurement of the electron cyclotron emission from high-temperature plasmas

International Nuclear Information System (INIS)

Efthimion, P.C.; Arunasalam, V.; Bitzer, R.; Campbell, L.; Hosea, J.C.

1979-03-01

A fast-scanning heterodyne receiver was developed that measures the fundamental cyclotron emission from the PLT plasma and thus ascertains the time evolution of the electron temperature profile. The receiver scans 60 to 90 GHz every 10 milliseconds and is interfaced to a computer for completely automated calibrated temperature measurements

The application of dynamic method for the temperature measurement of gas destruction in a plasma reactor

International Nuclear Information System (INIS)

Ryszard, Sarba

2009-01-01

This paper presents an experimental and theoretical study of the conversion of measuring probe temperature into hot gas temperature. The author gives a solution to the problem of a destruction temperature measurement in a plasma reactor. The temperature conversion is based on the thermodynamic similarity theory and statistical thermodynamics verification. The experimental measurements of the hot gas temperature have been made in the place where it considerably exceeds the melting point of the measuring probe material. The heat exchange phenomenon on the measuring probe's surface with the hot gas surrounding it is described by a forced convection equation. An analysis has been made of the heat flowing in and out of the measuring probe. The experimental part of the paper includes: an experimental measurement of gas velocity by means of luminous particles, a hot gas measurement for one distance from a nozzle and different diameters of the measuring probe, as well as different probing velocities. Numerical simulations have been made of the temperature distribution in a plasma jet. The experimental results are congruent with theoretical predictions. The aim of this research is a contribution to the structuring of a mathematical model of mass and energy balance in the processes of NHF 2 CL waste destruction.

Measurement of electron density and electron temperature of a cascaded arc plasma using laser Thomson scattering compared to an optical emission spectroscopic approach

Science.gov (United States)

Yong, WANG; Cong, LI; Jielin, SHI; Xingwei, WU; Hongbin, DING

2017-11-01

As advanced linear plasma sources, cascaded arc plasma devices have been used to generate steady plasma with high electron density, high particle flux and low electron temperature. To measure electron density and electron temperature of the plasma device accurately, a laser Thomson scattering (LTS) system, which is generally recognized as the most precise plasma diagnostic method, has been established in our lab in Dalian University of Technology. The electron density has been measured successfully in the region of 4.5 × 1019 m-3 to 7.1 × 1020 m-3 and electron temperature in the region of 0.18 eV to 0.58 eV. For comparison, an optical emission spectroscopy (OES) system was established as well. The results showed that the electron excitation temperature (configuration temperature) measured by OES is significantly higher than the electron temperature (kinetic electron temperature) measured by LTS by up to 40% in the given discharge conditions. The results indicate that the cascaded arc plasma is recombining plasma and it is not in local thermodynamic equilibrium (LTE). This leads to significant error using OES when characterizing the electron temperature in a non-LTE plasma.

Spectroscopic measurements of plasma temperatures and electron number density in a uranium hollow cathode discharge lamp

International Nuclear Information System (INIS)

Shah, M.L.; Suri, B.M.; Gupta, G.P.

2015-01-01

The HCD (Hollow Cathode Discharge) lamps have been used as a source of free atoms of any metal, controllable by direct current in the lamp. The plasma parameters including neutral species temperature, atomic excitation temperature and electron number density in a see-through type, homemade uranium hollow cathode discharge lamp with neon as a buffer gas have been investigated using optical emission spectroscopic techniques. The neutral species temperature has been measured using the Doppler broadening of a neon atomic spectral line. The atomic excitation temperature has been measured using the Boltzmann plot method utilizing uranium atomic spectral lines. The electron number density has been determined from the Saha-Boltzmann equation utilizing uranium atomic and ionic spectral lines. To the best of our knowledge, all these three plasma parameters are simultaneously measured for the first time in a uranium hollow cathode discharge lamp

Characteristics of an intrinsic germanium detector for measurement of soft x-rays from high-temperature plasmas

International Nuclear Information System (INIS)

Kumagai, Katsuaki; Matoba, Tohru; Funahashi, Akimasa; Kawakami, Tomohide

1976-09-01

An intrinsic germanium (Ge(I)) detector has been prepared for measurement of soft X-ray spectra from high-temperature tokamak plasmas. Its characteristics of photo-peak efficiency, escape-peak and Compton scattering were calibrated with standard radioisotopes and soft X-rays from the JFT-2a plasma, and compared with those of a lithium-drifted silicon (Si(Li)) detector. Features of the Ge(I) detector are as follows: (i) high detection efficiency in the high energy range, (ii) wide energy range for measurement of soft X-ray spectra, and (iii) low Compton scattering effect in measurement of continuous spectra. Its dead-layer depth is about 0.06μm, and the minimum detectable energies in the Ge(I) detector are similar to those in the Si(Li) detector. The Ge(I) detector is effective for measuring soft X-ray spectra from high-temperature tokamak plasmas. (auth.)

Pulse pileup effects of plasma electron temperature measurements by soft x-ray energy analysis

International Nuclear Information System (INIS)

Dyer, G.R.; Neilson, G.H.; Kelley, G.G.

1978-10-01

The electron temperature of hot plasmas is conveniently derived from bremsstrahlung spectra obtained by pulse-height analysis using a lithium-compensated silicon detector. Time-resolved temperature measurements require high counting rates, with ultimate rate limited by pulse pileup. To evaluate this limit, spectral distortion due to pileup and consequent effects on temperature determination are investigated. Expressions for distorted spectra are derived as functions of Maxwellian temperature and pileup fraction for both square and triangular pulse shapes. A comparison of temperatures obtained from distorted spectra with actual values indicates that measurements with less than 10% error can be made in the absence of line radiation, even from spectra containing 40% pileup

Measuring the Plasma Density of a Ferroelectric Plasma Source in an Expanding Plasma

International Nuclear Information System (INIS)

Dunaevsky, A.; Fisch, N.J.

2003-01-01

The initial density and electron temperature at the surface of a ferroelectric plasma source were deduced from floating probe measurements in an expanding plasma. The method exploits negative charging of the floating probe capacitance by fast flows before the expanding plasma reaches the probe. The temporal profiles of the plasma density can be obtained from the voltage traces of the discharge of the charged probe capacitance by the ion current from the expanding plasma. The temporal profiles of the plasma density, at two different distances from the surface of the ferroelectric plasma source, could be further fitted by using the density profiles for the expanding plasma. This gives the initial values of the plasma density and electron temperature at the surface. The method could be useful for any pulsed discharge, which is accompanied by considerable electromagnetic noise, if the initial plasma parameters might be deduced from measurements in expanding plasma

Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

International Nuclear Information System (INIS)

Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

2009-01-01

The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

Feasibility Studies of the Two Filters Method in TJ-II for Electron Temperature Measurements in High Density Plasmas

Energy Technology Data Exchange (ETDEWEB)

Baiao, D.; Medina, F.; Ochando, M.; Varandas, C.

2009-07-01

The TJ-II plasma soft X-ray emission was studied in order to establish an adequate setup for an electron temperature diagnostic suitable for high density, with spatial and temporal resolutions, based on the two-filters method. The preliminary experimental results reported were obtained with two diagnostics (an X-ray PHA based on a Ge detector and a tomography system) already installed in TJ-II stellarator. These results lead to the conclusion that the two-filters method was a suitable option for an electron temperature diagnostic for high-density plasmas in TJ-II. We present the design and fi rst results obtained with a prototype for the measurement of electron temperature in TJ-II plasmas heated with energetic neutral beams. This system consists in two AXUV20A detectors which measure the soft X-ray plasma emissivity trough beryllium filters of different thickness. From the two-filters technique it is possible to estimate the electron temperature. The analyses carried out allowed concluding which filter thicknesses are most suited for TJ-II plasmas, and enhanced the need of a computer code to simulate signals and plasma compositions. (Author) 7 refs.

Using Three-Body Recombination to Extract Electron Temperatures of Ultracold Plasmas

International Nuclear Information System (INIS)

Fletcher, R. S.; Zhang, X. L.; Rolston, S. L.

2007-01-01

Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of T e -9/2 . We measure three-body recombination in an ultracold neutral xenon plasma by detecting recombination-created Rydberg atoms using a microwave-ionization technique. With the accepted theory (expected to be applicable for weakly coupled plasmas) and our measured rates, we extract the plasma temperatures, which are in reasonable agreement with previous measurements early in the plasma lifetime. The resulting electron temperatures indicate that the plasma continues to cool to temperatures below 1 K

A review of the methods to measure the ion temperature in a tokamak plasma

International Nuclear Information System (INIS)

Zurro Hernandez, B.; Perez-Navarro Gomez, A.

1976-01-01

The most important methods to measure the ion temperatu--re in a Tokamak plasma are reviewed, e.g. energy analysis of the fast neutrals which leave out the plasma, Doppler broadening of the emision spectral lines and fusion neutron analysis. It is discussed their bounds so as the advantages and drawbacks of each one. Other methods of some interest in the future are outlined. (author) [es

Ultra-violet recombination continuum electron temperature measurements in a non-equilibrium atmospheric argon plasma

International Nuclear Information System (INIS)

Gordon, M.H.; Kruger, C.H.

1991-01-01

Emission measurements of temperature and electron density have been made downstream of a 50 kW induction plasma torch at temperatures and electron densities ranging between 6000 K and 8500 K and 10 to the 20th and 10 to the 21st/cu cm, respectively. Absolute and relative atomic line intensities, and absolute recombination continuum in both the visible and the UV were separately interpreted in order to characterize a recombining atmospheric argon plasma. Continuum measurements made in the UV at 270 nm were used to directly determine the kinetic electron temperature, independent of a Boltzmann equilibrium, assuming only that the electron velocity distribution is Maxwellian. The data indicate that a nonequilibrium condition exists in which the bound-excited and free electrons are nearly in mutual equilibrium down to the 4P level for electron densities as low as 2 x 10 to the 20th/cu m but that both are overpopulated with respect to the ground state due to finite recombination rates. 13 refs

Measurements of electron density and temperature profiles in plasma produced by Nike KrF laser for laser plasma instability research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Karasik, M.; Chan, L. Y.

2015-08-01

A grid image refractometer (GIR) has been implemented at the Nike krypton fluoride laser facility of the Naval Research Laboratory. This instrument simultaneously measures propagation angles and transmissions of UV probe rays (λ = 263 nm, Δt = 10 ps) refracted through plasma. We report results of the first Nike-GIR measurement on a CH plasma produced by the Nike laser pulse (˜1 ns FWHM) with the intensity of 1.1 × 1015 W/cm2. The measured angles and transmissions were processed to construct spatial profiles of electron density (ne) and temperature (Te) in the underdense coronal region of the plasma. Using an inversion algorithm developed for the strongly refracted rays, the deployed GIR system probed electron densities up to 4 × 1021 cm-3 with the density scale length of 120 μm along the plasma symmetry axis. The resulting ne and Te profiles are verified to be self-consistent with the measured quantities of the refracted probe light.

Ion temperature measurements of turbulently heated TRIAM-1 plasmas by the Doppler-broadening of visible lines

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Toi, K; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1980-07-01

The ion temperature of the turbulently heated TRIAM-1 plasma is obtained from the Doppler-broadening of visible lines. The radial profiles of the volume emission of visible lines are measured beforehand to examine whether the volume emissions are localized at a specified position of the minor cross-section of the plasma or not. The ion temperature of the specified position is determined from these profiles. The time behaviour of thus obtained Doppler ion temperature shows a good agreement with that of the one derived from the Neutral Energy Analyzer.

Results of measurements of the ion temperature profile of ECR heated plasmas in the L-2M stellarator

International Nuclear Information System (INIS)

Voronov, G.S.; Voronova, E.V.; Grebenshchikov, S.E.

2005-01-01

After boronization of the vacuum chamber of the L-2M stellarator, the confinement characteristics and the electron temperature profile changed markedly. In this connection, our immediate task was to carry out studies of the behavior of the ion temperature under these conditions. Previous measurements of Ti were performed by analyzing the energy distribution of fast hydrogen ions produced by charge exchange. In recent studies, the ion temperature was determined from Doppler broadening of spectral lines of impurity ions. With the help of a set of mirrors, the plasma radiation was focused on the entrance slit of a VMS-1 monochromator (D/F=1:6.5, F=600 mm, 1200 lines/mm,1.3 nm/mm, 200 - 800 nm). The detector was a CCD plate (1040 1 140 pixels of size 16 1 6 ∝ m) covered in part with an opaque screen. The plasma spectrum produced in the uncovered area was rapidly scanned and copied into the covered region. With this partial exposition method, the rate of recording was successfully increased up to 1000 frames per second. The instrument function of the whole system was 0.04 nm, which corresponds to Ti ∼1 eV for hydrogen and ∼17 eV for boron ions. The plasma ion temperature is considerably higher, so the accuracy of measurements of Ti is limited primarily by a low intensity of signals from the plasma with a low impurity concentration. The results of measurements of the evolution of HeII, BII, and BIV ions temperature during the ECR heating of a helium plasma are shown in the figure. The plasma density in these experiments was ∼2.10 19 m -3 , and the gyrotron pulse power was ∼200 kW. The results of measurements of Ti were compared with the time evolution of the ion temperature calculated by using the TRANSZ code. The latter includes a complete set of neoclassical equations and involves additional anomalous fluxes corresponding to accepted empirical scalings. The calculated values of Ti are in fair agreement with the measured ones

2-D Temperature Mapping in Fluorocarbon Plasmas

Science.gov (United States)

Steffens, Kristen L.; Sobolewski, Mark A.

2005-09-01

Two-dimensional maps of rotational temperature in CF4 plasmas were determined using planar laser-induced fluorescence measurements of CF A2Σ+ - X2Π (1,0). Rotational temperatures are expected to be in equilibrium with gas temperatures under the present conditions. Experiments were performed in a capacitively-coupled, parallel-plate reactor at pressures from 27 Pa to 107 Pa and powers of 10 W to 30 W. The effects of electrode cooling and having a wafer present were also examined. Measured temperatures ranged between 273 K±15 K and 480 K±15 K. The strong temperature gradients found in these plasmas can have serious effects on density measurements that probe a single rotational level, as well as on reaction rate constants and interpretation of density gradients.

Measurement of spatially resolved gas-phase plasma temperatures by optical emission and laser-induced fluorescence spectroscopy

International Nuclear Information System (INIS)

Davis, G.P.; Gottscho, R.A.

1983-01-01

Knowledge of the energy distributions of particles in glow discharges is crucial to the understanding and modeling of plasma reactors used in microelectronic manufacturing. Reaction rates, available product channels, and transport phenomena all depend upon the partitioning of energy in the discharge. Because of the nonequilibrium nature of glow discharges, however, the distribution of energy among different species and among different degrees of freedom cannot be characterized simply by one temperature. The extent to which different temperatures are needed for each degree of freedom and for each species is not known completely. How plasma operating conditions affect these energy distributions is also an unanswered question. We have investigated the temperatures of radicals, ions, and neutrals in CCl 4 , CCl 4 /N 2 (2%), and N 2 discharges. In the CCl 4 systems, we probed the CCl rotational and vibrational energy distributions by laser-induced fluorescence spectroscopy. The rotational distribution always appeared to be thermal but under identical operating conditions was found to be roughly-equal400 K colder than the vibrational distribution. The rotational temperature at any point in the discharge was strongly dependent upon both applied power and surface temperature. Thermal gradients as large as 10 2 K mm -1 were observed near electrode surfaces but the bulk plasmas were isothermal. When 2% N 2 was added to a CCl 4 discharge, N 2 second positive emission was observed and used to estimate the N 2 rotational temperature. The results suggest that emission from molecular actinometers can be used to measure plasma temperatures, providing such measurements are not made in close proximity to surfaces

Application of SSNTDs for measurements of fusion reaction products in high-temperature plasma experiments

Energy Technology Data Exchange (ETDEWEB)

Malinowska, A., E-mail: a.malinowska@ipj.gov.p [Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk (Poland); Szydlowski, A.; Malinowski, K. [Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk (Poland); Sadowski, M.J. [Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk (Poland); Institute of Plasma Physics and Laser Microfusion (IPPLM), 00-908 Warsaw (Poland); Zebrowski, J. [Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk (Poland); Scholz, M.; Paduch, M.; Zielinska, E. [Institute of Plasma Physics and Laser Microfusion (IPPLM), 00-908 Warsaw (Poland); Jaskola, M.; Korman, A. [Andrzej Soltan Institute for Nuclear Studies (IPJ), 05-400 Otwock-Swierk (Poland)

2009-10-15

The paper describes the application of SSNTDs of the PM-355 type to diagnostics of reaction products emitted from high-temperature deuterium plasmas produced in Plasma Focus (PF) facilities. Acceleration processes occurring in plasma lead often to the generation of high-energy ion beams. Such beams induce nuclear reactions and contribute to the emission of fast neutrons, fusion protons and alpha particles from PF discharges with a deuterium gas. Ion measurements are of primary importance for understanding the mechanisms of the physical processes which drive the charged-particle acceleration. The main aim of the present studies was to perform measurements of spatial- and energy-distributions of fusion-reaction protons (about 3 MeV) within a PF facility. Results obtained from energy measurements were compared with the proton-energy spectra computed theoretically. The protons were measured by means of a set of ion pinhole cameras equipped with PM-355 detectors, which were placed at different angles relative to the electrode axis of the PF facility.

Measurement of Debye length in laser-produced plasma.

Science.gov (United States)

Ehler, W.

1973-01-01

The Debye length of an expanded plasma created by placing an evacuated chamber with an entrance slit in the path of a freely expanding laser produced plasma was measured, using the slab geometry. An independent measurement of electron density together with the observed value for the Debye length also provided a means for evaluating the plasma electron temperature. This temperature has applications in ascertaining plasma conductivity and magnetic field necessary for confinement of the laser produced plasma. Also, the temperature obtained would be useful in analyzing electron-ion recombination rates in the expanded plasma and the dynamics of the cooling process of the plasma expansion.

Measurements of ion temperature and plasma hydrogenic composition by collective Thomson scattering in neutral beam heated discharges at TEXTOR

DEFF Research Database (Denmark)

Stejner Pedersen, Morten; Salewski, Mirko; Korsholm, Søren Bang

2013-01-01

A method is developed to perform plasma composition and ion temperature measurements across the plasma minor radius in TEXTOR based on ion cyclotron structures in collective Thomson scattering spectra. By gradually moving the scattering volume, we obtain measurements across the outer midplane of ...

Measurements of Laser Plasma Instability (LPI) and Electron Density/Temperature Profiles in Plasmas Produced by the Nike KrF Laser

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

2016-10-01

We will present results of simultaneous measurements of LPI-driven light scattering and density/temperature profiles in CH plasmas produced by the Nike krypton fluoride laser (λ = 248 nm). The primary diagnostics for the LPI measurement are time-resolved spectrometers with absolute intensity calibration in spectral ranges relevant to the optical detection of stimulated Raman scattering or two plasmon decay. The spectrometers are capable of monitoring signal intensity relative to thermal background radiation from plasma providing a useful way to analyze LPI initiation. For further understanding of LPI processes, the recently implemented grid image refractometer (Nike-GIR)a is used to measure the coronal plasma profiles. In this experiment, Nike-GIR is equipped with a 5th harmonic probe laser (λ = 213 nm) in attempt to probe into a high density region over the previous peak density with λ = 263 nm probe light ( 4 ×1021 cm-3). The LPI behaviors will be discussed with the measured data sets. Work supported by DoE/NNSA.

Multi parametric sensitivity study applied to temperature measurement of metallic plasma facing components in fusion devices

International Nuclear Information System (INIS)

Aumeunier, M-H.; Corre, Y.; Firdaouss, M.; Gauthier, E.; Loarer, T.; Travere, J-M.; Gardarein, J-L.; EFDA JET Contributor

2013-06-01

In nuclear fusion experiments, the protection system of the Plasma Facing Components (PFCs) is commonly ensured by infrared (IR) thermography. Nevertheless, the surface monitoring of new metallic plasma facing component, as in JET and ITER is being challenging. Indeed, the analysis of infrared signals is made more complicated in such a metallic environment since the signals will be perturbed by the reflected photons coming from high temperature regions. To address and anticipate this new measurement environment, predictive photonic models, based on Monte-Carlo ray tracing (SPEOS R CAA V5 Based), have been performed to assess the contribution of the reflective part in the total flux collected by the camera and the resulting temperature error. This paper deals with the effects of metals features, as the emissivity and reflectivity models, on the accuracy of the surface temperature estimation. The reliability of the features models is discussed by comparing the simulation with experimental data obtained with the wide angle IR thermography system of JET ITER like wall. The impact of the temperature distribution is studied by considering two different typical plasma scenarios, in limiter (ITER start-up scenario) and in X-point configurations (standard divertor scenario). The achievable measurement performances of IR system and risks analysis on its functionalities are discussed. (authors)

Spectral measurements of electron temperature in nonequilibrium highly ionized He plasma

International Nuclear Information System (INIS)

Korshunov, O V; Chinnov, V F; Kavyrshin, D I; Ageev, A G

2016-01-01

It has been experimentally shown that highly ionized He arc plasma does not achieve local thermodynamic equilibrium expected for plasmas with electron concentrations above 1 × 10 16 cm -3 like argon plasma. We have found that the reason for this deviation is strong nonisotropy of plasma. Triple electron recombination with temperatures of 2.5-3 eV is almost absent. Charged particles move from the arc ( r = 1 mm) to chamber walls due to ambipolar diffusion creating ionization nonequilibrium over the excited states rendering Boltzmann distribution and Saha equation inapplicable for determining electron temperature. A method for determining electron temperature is suggested that is based on using the relative intensities of the atomic and ion lines. Its advantage lies in an energy gap between these lines’ states over 50 eV that reduces the influence of nonequilibrium on the result. This influence can be taken into account if the ionization energies of emitting states of atom and ion have close values. The suggested method can be expanded for any media including those with dimensional nonisotropy that have both atomic and ion lines in their emission spectra. (paper)

Time-resolved tomographic measurements of temperatures in a thermal plasma jet

Czech Academy of Sciences Publication Activity Database

Hlína, Jan; Šonský, Jiří

2010-01-01

Roč. 43, č. 5 (2010), s. 1-9 ISSN 0022-3727 Institutional research plan: CEZ:AV0Z20570509 Keywords : thermal plasma jet * optical diagnostics * temperature distribution Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.105, year: 2010

Measurement of Temperature in the Steam Arcjet During Plasma Arc Cutting

Czech Academy of Sciences Publication Activity Database

Mašláni, Alan; Sember, Viktor; Stehrer, T.; Pauser, H.

2013-01-01

Roč. 33, č. 3 (2013), s. 593-604 ISSN 0272-4324 R&D Projects: GA ČR GAP205/11/2070 Institutional support: RVO:61389021 Keywords : Plasma arc cutting * Optical emission spectroscopy * Plasma temperature * Steam torch Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.599, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs11090-013-9443-y.pdf

Turbulence measurements in fusion plasmas

International Nuclear Information System (INIS)

Conway, G D

2008-01-01

Turbulence measurements in magnetically confined toroidal plasmas have a long history and relevance due to the detrimental role of turbulence induced transport on particle, energy, impurity and momentum confinement. The turbulence-the microscopic random fluctuations in particle density, temperature, potential and magnetic field-is generally driven by radial gradients in the plasma density and temperature. The correlation between the turbulence properties and global confinement, via enhanced diffusion, convection and direct conduction, is now well documented. Theory, together with recent measurements, also indicates that non-linear interactions within the turbulence generate large scale zonal flows and geodesic oscillations, which can feed back onto the turbulence and equilibrium profiles creating a complex interdependence. An overview of the current status and understanding of plasma turbulence measurements in the closed flux surface region of magnetic confinement fusion devices is presented, highlighting some recent developments and outstanding problems.

Measurement of density and electron temperature of a decaying plasma in 4.2 K helium gases

International Nuclear Information System (INIS)

Kimura, T.; Minami, K.

1986-01-01

As is well known, the coupling constant Γ of a plasma is defined as the ratio of the average Coulomb energy to the average kinetic energy. Plasmas with Γ not much less than unity are called strongly coupled plasmas or non-ideal plasmas. Such plasmas, high density or low temperature, can be produced by laser implosion, shock waves etc. In the present report, the authors' attempt to generate a non-ideal plasma in a different way from previous ones. They observe a late period of a decaying plasma in helium gases at a temperature less than 4.2 K. An afterglow in cryogenic helium gases was studied previously. In that study, the authors measured the density of the order of 10/sup 12/ cm/sup -3/ by the method of transmission of X-band microwaves. In the present case, plasma is observed in a cylindrical cavity of TE/sub 011/ mode at 2.83 GHz immersed in liquid helium. The size of the cavity is 166 mm inner diameter and 83 mm length. One end wall is made by thin mesh through which plasmas produced by pulse discharge of 750 A, 1 μsec are fed. The loaded Q without plasma is 5300. The pressure of helium gas is changed from 0.03 to 1.3 Torr

One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

International Nuclear Information System (INIS)

Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

1996-10-01

In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma -conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding -Ar-Ne plasma. An absolutely calibrated, high resolution space- and time- resolving Johann crystal spectrometer was used to infer the electron temperature Te from the slope of the hydrogenlike Ne free-bound continuum, and the ion density ni from the Stark broadening of the Ar heliunlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MM models predict a radiating region denser and cooler than measured

Tunnel probes for measurements of the electron and ion temperature in fusion plasmas

Czech Academy of Sciences Publication Activity Database

Gunn, J. P.; Schrittwieser, R.; Balan, P.; Ionita, C.; Stöckel, Jan; Adámek, Jiří; Ďuran, Ivan; Hron, Martin; Pánek, Radomír; Bařina, O.; Hrach, R.; Vicher, M.; Van Oost, G.; Van Rompuy, T.; Martines, E.

2004-01-01

Roč. 75, č. 10 (2004), s. 4328-4330 ISSN 0034-6748. [Topical Conference on High-Temperature Plasma Diagnostics/15th./. San Diego, 19.04.2004-22.04.2004] R&D Projects: GA ČR GA202/03/0786 Institutional research plan: CEZ:AV0Z2043910 Keywords : Tokamak * electron temperature * ion temperature * plasma diagnostics Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.226, year: 2004

Main-ion temperature and plasma rotation measurements based on scattering of electron cyclotron heating waves in ASDEX Upgrade

DEFF Research Database (Denmark)

Pedersen, Morten Stejner; Rasmussen, Jesper; Nielsen, Stefan Kragh

2017-01-01

We demonstrate measurements of spectra of O-mode electron cyclotron resonance heating (ECRH) waves scattered collectively from microscopic plasma fluctuations in ASDEX Upgrade discharges with an ITER-like ECRH scenario. The measured spectra are shown to allow determination of the main ion...... temperature and plasma rotation velocity. This demonstrates that ECRH systems can be exploited for diagnostic purposes alongside their primary heating purpose in a reactor relevant scenario....

Spectroscopic diagnostics of high temperature plasmas

International Nuclear Information System (INIS)

Moos, W.

1990-01-01

A three-year research program for the development of novel XUV spectroscopic diagnostics for magnetically confined fusion plasmas is proposed. The new diagnostic system will use layered synthetic microstructures (LSM) coated, flat and curved surfaces as dispersive elements in spectrometers and narrow band XUV filter arrays. In the framework of the proposed program we will develop impurity monitors for poloidal and toroidal resolved measurements on PBX-M and Alcator C-Mod, imaging XUV spectrometers for electron density and temperature fluctuation measurements in the hot plasma core in TEXT or other similar tokamaks and plasma imaging devices in soft x-ray light for impurity behavior studies during RF heating on Phaedrus T and carbon pellet ablation in Alcator C-Mod. Recent results related to use of multilayer in XUV plasma spectroscopy are presented. We also discuss the latest results reviewed to q o and local poloidal field measurements using Zeeman polarimetry

Preliminary scaling laws for plasma current, ion kinetic temperature, and plasma number density in the NASA Lewis bumpy torus plasma

Science.gov (United States)

Roth, J. R.

1976-01-01

Parametric variation of independent variables which may affect the characteristics of bumpy torus plasma have identified those which have a significant effect on the plasma current, ion kinetic temperature, and plasma number density, and those which do not. Empirical power law correlations of the plasma current, and the ion kinetic temperature and number density were obtained as functions of potential applied to the midplane electrode rings, the background neutral gas pressure, and the magnetic field strength. Additional parameters studied included the type of gas, the polarity of the midplane electrode rings, the mode of plasma operation, and the method of measuring the plasma number density. No significant departures from the scaling laws appear to occur at the highest ion kinetic temperatures or number densities obtained to date.

Study on factors affecting the droplet temperature in plasma MIG welding process

Science.gov (United States)

Mamat, Sarizam Bin; Tashiro, Shinichi; Tanaka, Manabu; Yusoff, Mahani

2018-04-01

In the present study, the mechanism to control droplet temperature in the plasma MIG welding was discussed based on the measurements of the droplet temperature for a wide range of MIG currents with different plasma electrode diameters. The measurements of the droplet temperatures were conducted using a two color temperature measurement method. The droplet temperatures in the plasma MIG welding were then compared with those in the conventional MIG welding. As a result, the droplet temperature in the plasma MIG welding was found to be reduced in comparison with the conventional MIG welding under the same MIG current. Especially when the small plasma electrode diameter was used, the decrease in the droplet temperature reached maximally 500 K. Also, for a particular WFS, the droplet temperatures in the plasma MIG welding were lower than those in the conventional MIG welding. It is suggested that the use of plasma contributes to reducing the local heat input into the base metal by the droplet. The presence of the plasma surrounding the wire is considered to increase the electron density in its vicinity, resulting in the arc attachment expanding upwards along the wire surface to disperse the MIG current. This dispersion of MIG current causes a decrease in current density on the droplet surface, lowering the droplet temperature. Furthermore, dispersed MIG current also weakens the electromagnetic pinch force acting on the neck of the wire above the droplet. This leads to a larger droplet diameter with increased surface area through lower frequency of droplet detachment to decrease the MIG current density on the droplet surface, as compared to the conventional MIG welding at the same MIG current. Thus, the lower droplet temperature is caused by the reduction of heat flux into the droplet. Consequently, the mechanism to control droplet temperature in the plasma MIG welding was clarified.

Observation of soft x-ray radiation from Heliotron E plasmas by the absorption method for the measurement of electron temperatures

International Nuclear Information System (INIS)

Kaneko, H.; Tohda, T.; Iiyoshi, A.

1989-01-01

An absorption method of soft x ray is applied to Heliotron E plasmas for measurement of the electron temperature. Nitrogen gas is used as an absorber for convenience, owing to its accurate, uniform, and easily controllable density. The general feature of the absorption method for measurement of the electron temperature is discussed using a model with two parameters: the generalized thickness of the absorber and the electron temperature. The energy resolution of this method is not sufficient as a general method for spectral analysis. Hence, it is necessary to assume in advance such a model spectrum as consists of bremsstrahlung, recombination radiation, and impurity line radiation. Since the spectrum is always assumed before the analysis, we should try to find the origins of deformation of the energy spectrum and to correct the contribution. The effect of line emission from impurity ions to the estimated electron temperature is evaluated as a function of the electron temperature and the energy of the line relative to the generalized absorber thickness used in the measurement. An actual spectrum is measured by a pulse-height analysis (PHA) of the soft x ray. The one clear line, from chlorine, is not significant in the present determination of the electron temperature by the absorption method. Another possible line from iron at energy less than 1 keV is included in the analysis. Using a convenient method for determination of local emissivity from a chord-integrated emissivity, the electron temperature is determined from the local emissivity. The observed broad electron-temperature profile might be an artifact due to recombination radiation of the highly ionized ion diffused out of the hot core of the plasma. It is confirmed that the absorption method gives absolute measurement of the electron temperature at the plasma center, when additional information on impurity lines are given by PHA

One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

International Nuclear Information System (INIS)

Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

1997-01-01

In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding Ar-Ne plasma. An absolutely calibrated, high resolution space- and time-resolving Johann crystal spectrometer was used to infer the electron temperature T e from the slope of the hydrogenlike Ne free-bound continuum, and the ion density n i from the Stark broadening of the Ar heliumlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill, which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MHD models predict a radiating region denser and cooler than measured. copyright 1997 American Institute of Physics

Measuring methods for the TFR plasma diagnostics

International Nuclear Information System (INIS)

Etievant, C.

1975-02-01

The measuring methods in operation or still under development for the diagnostics of the TFR plasma parameters (ion and electron temperatures, electron density, current density are reviewed, the diagnostics of the electrical behavior of the discharge, the neutral gas densities, the impurities and the parameters of the plasma turbulence being also investigated. Actual works are principally devoted to: improving ion temperature measurements by the possible use of the Doppler effect or infra-red incoherent scattering; improving n(e) and T(e) measurement by Thomson scattering; measuring the poloidal field and current density; measuring impurities by X and UV spectroscopy and measuring instabilities and turbulence [fr

Plasma core electron density and temperature measurements using CVI line emissions in TCABR Tokamak

Energy Technology Data Exchange (ETDEWEB)

Nascimento, F. do, E-mail: fellypen@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Componentes Semicondutores; Machida, M. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Severo, J.H.F.; Sanada, E.; Ronchi, G. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

2015-08-15

In this work, we present results of electron temperature (T{sub e} ) and density (n {sub e} ) measurements obtained in Tokamak Chauffage Alfven Bresilien (TCABR) tokamak using visible spectroscopy from CVI line emissions which occurs mainly near the center of the plasma column. The presented method is based on a well-known relationship between the particle flux (Γ {sub ion}) and the photon flux (ø {sub ion}) emitted by an ion species combined with ionizations per photon atomic data provided by the atomic data and analysis structure (ADAS) database. In the experiment, we measured the photon fluxes of three different CVI spectral line emissions, 4685.2, 5290.5, and 6200.6 Å (one line per shot). Using this method it was possible to find out the temporal evolution of T{sub e} and n{sub e} in the plasma. The results achieved are in good agreement with T{sub e} and n{sub e} measurements made using other diagnostic tools. (author)

Opacity measurements in shock-generated argon plasmas

Energy Technology Data Exchange (ETDEWEB)

Erskine, D.

1993-07-01

Dense plasmas having uniform and constant density and temperature are generated by passage of a planar shock wave through gas. The opacity of the plasma is accurately measured versus wavelength by recording the risetime of emitted light. This technique is applicable to a wide variety of species and plasma conditions. Initial experiments in argon have produced plasmas with 2 eV temperatures, 0.004--0.04 g/cm{sup 3} densities, and coupling parameters {Gamma} {approximately}0.3--0.7. Measurements in visible light are compared with calculations using the HOPE code. An interesting peak in the capacity at 400 nm is observed for the first time and is identified with the 4s-5p transition in excited neutral argon atoms.

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

Science.gov (United States)

Zanáška, M.; Adámek, J.; Peterka, M.; Kudrna, P.; Tichý, M.

2015-03-01

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents Isat-/Isat+ to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma of a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa.

Measuring temperatures with modified Kleiber 270B pyrometer

International Nuclear Information System (INIS)

Osch, E.V. van.

1995-05-01

At ECN a fast pyrometer is being used as a diagnostic tool for plasma disruption simulation experiments on candidate plasma facing materials for future thermonuclear fusion devices such as NET or ITER. The pyrometer is being used to measure the surface temperature response of the materials to short pulse high heat loads as induced by high power laser or electron beam, simulating the disrupting plasma's energy deposition. A procedure to measure surface temperatures without having to know surface emissivity in advance is described. The formulae needed in this procedure to obtain the correct temperature, starting from the initial incorrect temperature reading, are derived. Inversely, the formula to determine the emissivity of the surface when its temperature is known is equally derived. Finally, a small study on background level sensitivity is presented, showing the, in general, small effect of background on the temperature measurement. (orig.)

Time-dependent electron temperature diagnostics for high-power aluminum z-pinch plasmas

International Nuclear Information System (INIS)

Sanford, T.W.L.; Nash, T.J.; Mock, R.C.

1996-08-01

Time-resolved x-ray pinhole photographs and time-integrated radially-resolved x-ray crystal-spectrometer measurements of azimuthally-symmetric aluminum-wire implosions suggest that the densest phase of the pinch is composed of a hot plasma core surrounded by a cooler plasma halo. The slope of the free-bound x-ray continuum, provides a time-resolved, model-independent diagnostic of the core electron temperature. A simultaneous measurement of the time-resolved K-shell line spectra provides the electron temperature of the spatially averaged plasma. Together, the two diagnostics support a 1-D Radiation-Hydrodynamic model prediction of a plasma whose thermalization on axis produces steep radial gradients in temperature, from temperatures in excess of a kilovolt in the core to below a kilovolt in the surrounding plasma halo

Development of a six channel Fabry-Perot interferometer for continuous measurement of electron temperature of Tokamak plasma. Application to current diffusion study

International Nuclear Information System (INIS)

Talvard, M.

1984-10-01

It is shown how the properties of the electron cyclotron emission of a tokamak plasma can be used to measure the electron temperature. The design of a six channel Fabry-Perot interferometer is then described. This interferometer allows the measurement of the time evolution of the electron temperature profile of the plasma in the TFR tokamak. Using this technique interesting results have been obtained concerning the current penetration during the start up phase of a tokamak discharge [fr

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

International Nuclear Information System (INIS)

Zanáška, M.; Kudrna, P.; Tichý, M.; Adámek, J.; Peterka, M.

2015-01-01

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents I sat − /I sat + to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma of a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

Energy Technology Data Exchange (ETDEWEB)

Zanáška, M.; Kudrna, P.; Tichý, M. [Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 12116 Prague 2 (Czech Republic); Adámek, J. [Institute of Plasma Physics AS CR, v.v.i., Za Slovankou 3, 18200 Prague 8 (Czech Republic); Peterka, M. [Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 3, 12116 Prague 2 (Czech Republic); Institute of Plasma Physics AS CR, v.v.i., Za Slovankou 3, 18200 Prague 8 (Czech Republic)

2015-03-15

The ball-pen probe (BPP) is used for direct plasma potential measurements in magnetized plasma. The probe can adjust the ratio of the electron and ion saturation currents I{sub sat}{sup −}/I{sub sat}{sup +} to be close to one and therefore its I-V characteristic becomes nearly symmetric. If this is achieved, the floating potential of the BPP is close to the plasma potential. Because of its rather simple construction, it offers an attractive probe for measurements in magnetized plasma. Comparative measurements of plasma potential by BPPs of different dimensions as well as one Langmuir probe (LP) in an argon discharge plasma of a cylindrical magnetron were performed at various experimental conditions. An additional comparison by an emissive probe was also performed. All these types of probes provide similar values of plasma potential in a wide range of plasma parameters. Our results for three different BPP dimensions indicate that the BPP can be operated in a cylindrical magnetron DC argon discharge if the value of the ratio of the magnetic field and neutral gas pressure, B/p, is greater than approximately 10 mT/Pa.

Room-temperature atmospheric pressure plasma plume for biomedical applications

International Nuclear Information System (INIS)

Laroussi, M.; Lu, X.

2005-01-01

As low-temperature nonequilibrium plasmas come to play an increasing role in biomedical applications, reliable and user-friendly sources need to be developed. These plasma sources have to meet stringent requirements such as low temperature (at or near room temperature), no risk of arcing, operation at atmospheric pressure, preferably hand-held operation, low concentration of ozone generation, etc. In this letter, we present a device that meets exactly such requirements. This device is capable of generating a cold plasma plume several centimeters in length. It exhibits low power requirements as shown by its current-voltage characteristics. Using helium as a carrier gas, very little ozone is generated and the gas temperature, as measured by emission spectroscopy, remains at room temperature even after hours of operations. The plasma plume can be touched by bare hands and can be directed manually by a user to come in contact with delicate objects and materials including skin and dental gum without causing any heating or painful sensation

Atomic and molecular hydrogen gas temperatures in a low-pressure helicon plasma

Science.gov (United States)

Samuell, Cameron M.; Corr, Cormac S.

2015-08-01

Neutral gas temperatures in hydrogen plasmas are important for experimental and modelling efforts in fusion technology, plasma processing, and surface modification applications. To provide values relevant to these application areas, neutral gas temperatures were measured in a low pressure (radiofrequency helicon discharge using spectroscopic techniques. The atomic and molecular species were not found to be in thermal equilibrium with the atomic temperature being mostly larger then the molecular temperature. In low power operation (measurements near a graphite target demonstrated localised cooling near the sample surface. The temporal evolution of the molecular gas temperature during a high power 1.1 ms plasma pulse was also investigated and found to vary considerably as a function of pressure.

Thomson scattering measurements from asymmetric interpenetrating plasma flows

Energy Technology Data Exchange (ETDEWEB)

Ross, J. S., E-mail: ross36@llnl.gov; Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

2014-11-15

Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

Cylindrical implosion to measure the radiative properties of high density and temperature plasmas

International Nuclear Information System (INIS)

Xu Yan; Rose, S.J.

2000-01-01

Cylindrical implosion is of great interest because of its excellent diagnostic access. The authors present one-dimensional numerical simulations to explore the plasma conditions that may be achieved. Combined with the numerical data, the development of Rayleigh-Taylor instabilities and Richtmyer-Meshkov instabilities in those targets are estimated. The authors found that it is possible to achieve a high density and temperature plasma with a relatively low temperature and density gradient using a cylindrical implosion directly-driven by a high-power laser

Estimating plasma temperatures

International Nuclear Information System (INIS)

Nash, J.K.; Iglesias, C.A.; Chen, M.H.; Rogers, F.J.

1992-04-01

Recent laser-produced plasma experiments have relied on spectroscopic comparisons with models to infer plasma temperatures. The models use an experimentally determined value for the matter density as input and treat the temperature as a free parameter to obtain a best fit to the experimental absorption spectrum. However, uncertainties in the ionization balance theories lead to inferred temperatures that are model dependent. We report results of a new approach which combines high=quality atomic data with an ionization balance obtained from systematic expansions of the grand canonical ensemble. The latter avoids the ad hoc cutoffs required in free energy minimization schemes and includes Coulomb corrections usually neglected in other models. Comparisons to experimental spectra show excellent agreement

On improved understanding of plasma-chemical processes in complex low-temperature plasmas

Science.gov (United States)

Röpcke, Jürgen; Loffhagen, Detlef; von Wahl, Eric; Nave, Andy S. C.; Hamann, Stephan; van Helden, Jean-Piere H.; Lang, Norbert; Kersten, Holger

2018-05-01

Over the last years, chemical sensing using optical emission spectroscopy (OES) in the visible spectral range has been combined with methods of mid infrared laser absorption spectroscopy (MIR-LAS) in the molecular fingerprint region from 3 to 20 μm, which contains strong rotational-vibrational absorption bands of a large variety of gaseous species. This optical approach established powerful in situ diagnostic tools to study plasma-chemical processes of complex low-temperature plasmas. The methods of MIR-LAS enable to detect stable and transient molecular species in ground and excited states and to measure the concentrations and temperatures of reactive species in plasmas. Since kinetic processes are inherent to discharges ignited in molecular gases, high time resolution on sub-second timescales is frequently desired for fundamental studies as well as for process monitoring in applied research and industry. In addition to high sensitivity and good temporal resolution, the capacity for broad spectral coverage enabling multicomponent detection is further expanding the use of OES and MIR-LAS techniques. Based on selected examples, this paper reports on recent achievements in the understanding of complex low-temperature plasmas. Recently, a link with chemical modeling of the plasma has been provided, which is the ultimate objective for a better understanding of the chemical and reaction kinetic processes occurring in the plasma. Contribution to the Topical Issue "Fundamentals of Complex Plasmas", edited by Jürgen Meichsner, Michael Bonitz, Holger Fehske, Alexander Piel.

High-temperature plasma physics

International Nuclear Information System (INIS)

Furth, H.P.

1988-03-01

Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics

Spectroscopic and probe measurements of the electron temperature in the plasma of a pulse-periodic microwave discharge in argon

Energy Technology Data Exchange (ETDEWEB)

Andreev, V. V., E-mail: vvandreev@mail.ru; Vasileska, I., E-mail: ivonavasileska@yahoo.com; Korneeva, M. A., E-mail: korneevama@mail.ru [Peoples’ Friendship University of Russia (Russian Federation)

2016-07-15

A pulse-periodic 2.45-GHz electron-cyclotron resonance plasma source on the basis of a permanent- magnet mirror trap has been constructed and tested. Variations in the discharge parameters and the electron temperature of argon plasma have been investigated in the argon pressure range of 1 × 10{sup –4} to 4 × 10{sup –3} Torr at a net pulsed input microwave power of up to 600 W. The plasma electron temperature in the above ranges of gas pressures and input powers has been measured by a Langmuir probe and determined using optical emission spectroscopy (OES) from the intensity ratios of spectral lines. The OES results agree qualitatively and quantitatively with the data obtained using the double probe.

Rutherford scattering of neutral atoms: a technique for measuring plasma ion temperatures. An analysis of the applicability to the central cell plasma of TMX

International Nuclear Information System (INIS)

Granneman, E.H.A.

1980-01-01

Rutherford scattering of neutral particles by plasma ions is examined as a method for determining plasma ion in the central cell fo the Tandem Mirror Experiment (TMX). When a scattering configuration, consisting of a 20-keV-, 10-A-deuterium neutral beam and an energy analyzer with a 1% resolution, is arranged such that only neutral particles scattered by plasma ions over an angle of 10 0 are accepted, central-cell ion temperatures in the 30- to 1000-eV range can be measured. The count rate registered by the detector(s) is estimated to be 2000 counts/ms. Consequently, good statistical accuracy and time resolution are attainable simultaneously. The results of the calculation are presented such that the scaling of the count rates and the energy broadening with scattering angle, neutral-beam energy, ion temperature, and plasma density can easily be deduced. Neutral helium beams are also considered; they have some advantages over deuterium beams. The background signal, caused by neutral particles entering the detector after two successive charge-exchange collisions, is examined and ways to completely eliminate this background are indicated

Low Temperature Plasma Medicine

Science.gov (United States)

Graves, David

2013-10-01

Ionized gas plasmas near room temperature are used in a remarkable number of technological applications mainly because they are extraordinarily efficient at exploiting electrical power for useful chemical and material transformations near room temperature. In this tutorial address, I will focus on the newest area of low temperature ionized gas plasmas (LTP), in this case operating under atmospheric pressure conditions, in which the temperature-sensitive material is living tissue. LTP research directed towards biomedical applications such as sterilization, surgery, wound healing and anti-cancer therapy has seen remarkable growth in the last 3-5 years, but the mechanisms responsible for the biomedical effects have remained mysterious. It is known that LTP readily create reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS and RNS (or RONS), in addition to a suite of other radical and non-radical reactive species, are essential actors in an important sub-field of aerobic biology termed ``redox'' (or oxidation-reduction) biology. I will review the evidence suggesting that RONS generated by plasmas are responsible for their observed therapeutic effects. Other possible bio-active mechanisms include electric fields, charges and photons. It is common in LTP applications that synergies between different mechanisms can play a role and I will review the evidence for synergies in plasma biomedicine. Finally, I will address the challenges and opportunities for plasma physicists to enter this novel, multidisciplinary field.

Measuring deuterium permeation through tungsten near room temperature under plasma loading using a getter layer and ion-beam based detection

Directory of Open Access Journals (Sweden)

Stefan Kapser

2017-08-01

Full Text Available A method to measure deuterium permeation through tungsten near room temperature under plasma loading is presented. The permeating deuterium is accumulated in a getter layer of zirconium, titanium or erbium, respectively, on the unexposed side of the sample. Subsequently, the amount of deuterium in the getter is measured ex-situ using nuclear reaction analysis. A cover layer system on the getter prevents direct loading of the getter with deuterium from the gas phase during plasma loading. In addition, it enables the distinction of deuterium in the getter and at the cover surface. The method appears promising to add additional permeation measurement capabilities to deuterium retention experiments, also in other plasma devices, without the need for a complex in-situ permeation measurement setup.

Experimental investigation of ultraviolet laser induced plasma density and temperature evolution in air

International Nuclear Information System (INIS)

Thiyagarajan, Magesh; Scharer, John

2008-01-01

We present measurements and analysis of laser induced plasma neutral densities and temperatures in dry air by focusing 200 mJ, 10 MW high power, 193 nm ultraviolet ArF (argon fluoride) laser radiation to a 30 μm radius spot size. We examine these properties that result from multiphoton and collisional cascade processes for pressures ranging from 40 Torr to 5 atm. A laser shadowgraphy diagnostic technique is used to obtain the plasma electron temperature just after the shock front and this is compared with optical emission spectroscopic measurements of nitrogen rotational and vibrational temperatures. Two-color laser interferometry is employed to measure time resolved spatial electron and neutral density decay in initial local thermodynamic equilibrium (LTE) and non-LTE conditions. The radiating species and thermodynamic characteristics of the plasma are analyzed by means of optical emission spectroscopy (OES) supported by SPECAIR, a special OES program for air constituent plasmas. Core plasma rotational and vibrational temperatures are obtained from the emission spectra from the N 2 C-B(2+) transitions by matching the experimental spectrum results with the SPECAIR simulation results and the results are compared with the electron temperature just behind the shock wave. The plasma density decay measurements are compared with a simplified electron density decay model that illustrates the dominant three-and two-body recombination terms with good correlation

To the problem of electron temperature control in plasma

Energy Technology Data Exchange (ETDEWEB)

Galechyan, G.A. [Institute of Applied Problem of Physics, Yerevan (Armenia); Anna, P.R. [Raritan Valley Community College, Somerville, NJ (United States)

1995-12-31

One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO{sub 2} laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall.

To the problem of electron temperature control in plasma

International Nuclear Information System (INIS)

Galechyan, G.A.; Anna, P.R.

1995-01-01

One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO 2 laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall

Measurement of H and H2 populations in-situ in a low-temperature plasma by vacuum-ultraviolet laser-absorption spectroscopy

International Nuclear Information System (INIS)

Schlachter, A.S.; Young, A.T.; Stutzin, G.C.; Stearns, J.W.; Doebele, H.G.; Leung, K.N.; Kunkel, W.B.

1988-12-01

A new technique, vacuum-ultraviolet laser-absorption spectroscopy, has been developed to quantitatively determine the absolute density of H and H 2 within a plasma. The technique is particularly well suited to measurement in a plasma, where high charged particle and photon background complicate other methods of detection. The high selectivity and sensitivity of the technique allows for the measurement of the rotational-vibrational state distribution of H 2 as well as the translational temperature of the atoms and molecules. The technique has been used to study both pulsed and continuous H/sup /minus// ion-source plasma discharges. H 2 state distributions in a multicusp ''volume'' H/sup /minus// ion- source plasma show a high degree of internal excitation, with levels up to v = 5 and J = 8 being observed. The method is applicable for a very wide range of plasma conditions. Emission measurements from excited states of H are also reported. 17 refs., 9 figs

Measurements of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Karasik, M.; Chan, L.-Y.; Serlin, V.; Phillips, L.

2012-10-01

ExperimentsfootnotetextJ. Oh, et al, GO5.4, APS DPP (2010).^,footnotetextJ. L. Weaver, et al, GO5.3, APS DPP (2010). using Nike KrF laser observed LPI signatures from CH plasmas at the laser intensities above ˜1x10^15 W/cm^2. Knowing spatial profiles of temperature (Te) and density (ne) in the underdense coronal region (0 Nike LPI experiment, a side-on grid imaging refractometer (GIR)footnotetextR. S. Craxton, et al, Phys. Fluids B 5, 4419 (1993). is being deployed for measuring the underdense plasma profiles. The GIR will resolve Te and ne in space taking a 2D snapshot of probe laser (λ= 263 nm, δt = 10 psec) beamlets (50μm spacing) refracted by the plasma at a selected time during the laser illumination. Time-resolved spectrometers with an absolute-intensity-calibrated photodiode array and a streak camera will simultaneously monitor light emission from the plasma in spectral ranges relevant to Raman (SRS) and two plasmon decay (TDP) instabilities. The experimental study of effects of the plasma profiles on the LPI initiation will be presented.

Temperature of thermal plasma jets: A time resolved approach

Energy Technology Data Exchange (ETDEWEB)

Sahasrabudhe, S N; Joshi, N K; Barve, D N; Ghorui, S; Tiwari, N; Das, A K, E-mail: sns@barc.gov.i [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 094 (India)

2010-02-01

Boltzmann Plot method is routinely used for temperature measurement of thermal plasma jets emanating from plasma torches. Here, it is implicitly assumed that the plasma jet is 'steady' in time. However, most of the experimenters do not take into account the variations due to ripple in the high current DC power supplies used to run plasma torches. If a 3-phase transductor type of power supply is used, then the ripple frequency is 150 Hz and if 3- phase SCR based power supply is used, then the ripple frequency is 300 Hz. The electrical power fed to plasma torch varies at ripple frequency. In time scale, it is about 3.3 to 6.7 ms for one cycle of ripple and it is much larger than the arc root movement times which are within 0.2 ms. Fast photography of plasma jets shows that the luminosity of plasma jet also varies exactly like the ripple in the power supply voltage and thus with the power. Intensity of line radiations varies nonlinearly with the instantaneous power fed to the torch and the simple time average of line intensities taken for calculation of temperature is not appropriate. In this paper, these variations and their effect on temperature determination are discussed and a method to get appropriate data is suggested. With a small adaptation discussed here, this method can be used to get temperature profile of plasma jet within a short time.

Application of low-temperature plasma for the synthesis of hydrogenated graphene (graphane)

Science.gov (United States)

Shavelkina, M. B.; Amirov, R. H.; Katarzhis, V. A.; Kiselev, V. I.

2017-12-01

The possibility of a direct synthesis of hydrogenated graphene in decomposition of methane by means of low-temperature plasma was investigated. A DC plasma torch with an expanding channel-anode, a vortex gas supply and a self-setting arc length was used as a generator of low-temperature plasma. Argon was used as the plasma-forming gas. The temperatures of argon plasma and with methane addition to it were determined on the basis of spectral measurements. The synthesis products were characterized by electron microscopy and thermogravimetry. The effect of hydrogenated graphene as a nanomodifier on the properties of the cubic boron nitride based functional ceramics was investigated.

13. TOPICAL CONFERENCE ON HIGH TEMPERATURE PLASMA DIAGNOSTICS SCIENTIFIC PROGRAM

International Nuclear Information System (INIS)

Barnes, C.

2000-01-01

Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either overdense, operating at high density relative to the magnetic field (e.g. ω pe >> (Omega) ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (τ > 2). Electron Bernstein waves (EBWs) are electrostatic waves which can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large K i . This talk reports on measurements of EBW emission on the CDX-U spherical torus, where B 0 ∼ 2 kG, e > ∼ 10 13 cm -3 and T e ∼ 10 - 200 eV. Results will be presented for both direct detection of EBWs and for mode-converted EBW emission. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multi-point Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be ≤ T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe was employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Changes in the mode conversion efficiency may explain the observation of mode-converted EBW radiation temperatures below T e . Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where ω pe >> (Omega) ce

Modelling of a multi-temperature plasma composition

International Nuclear Information System (INIS)

Liani, B.; Benallal, R.; Bentalha, Z.

2005-01-01

Knowledge of plasma composition is very important for various plasma applications and prediction of plasma properties. The authors use the Saha equation and Debye length equation to calculate the non-local thermodynamic-equilibrium plasma composition. It has been shown that the model to 2T with T representing the temperature (electron temperature and heavy-particle temperature) described by Chen and Han [J. Phys. D 32(1999)1711] can be applied for a mixture of gases, where each atomic species has its own temperature, but the model to 4T is more general because it can be applicable to temperatures distant enough of the heavy particles. This can occur in a plasma composed of big- or macro-molecules. The electron temperature T e varies in the range 8000∼20000 K at atmospheric pressure. (authors)

Measurements of scrape-off layer ion-to-electron temperature ratio in Tore Supra ohmic plasmas

Czech Academy of Sciences Publication Activity Database

Kočan, M.; Gunn, J. P.; Pascal, J.-Y.; Bonhomme, G.; Devynck, P.; Ďuran, Ivan; Gauthier, E.; Ghendrih, P.; Marandet, Y.; Pegourie, B.; Vallet, J.-C.

390-391, - (2009), s. 1074-1077 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/18th./. Toledo, 26.05.2008-30.05. 2008] Institutional research plan: CEZ:AV0Z20430508 Keywords : Ion temperature * Electron temperature * Edge plasma * Tore Supra Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.933, year: 2009

A technique for temperature mapping in fluorocarbon plasmas using planar laser-induced fluorescence of CF

International Nuclear Information System (INIS)

Steffens, Kristen L.; Sobolewski, Mark A.

2004-01-01

Planar laser-induced fluorescence measurements of CF A 2 Σ + -X 2 Π(1,0) were used to determine two-dimensional maps of rotational temperature in CF 4 plasmas. Measured rotational temperatures are expected to be in equilibrium with the gas temperature due to the long chemical lifetime of CF relative to the collision rate. Experiments were performed in the capacitively coupled Gaseous Electronics Conference rf reference cell at pressures from 26.7 Pa (200 mTorr) to 107 Pa (800 mTorr) and powers of 10 to 30 W deposited in the plasma. Temperatures, which ranged from 273±15 K to 480±15 K, were fairly axially symmetric and increased with pressure and power. All plasmas were coolest near the electrodes, which provided a substantial sink for heat in the plasma. Highest temperatures were found at a radial position near the edge of the electrodes. The strong temperature gradients observed in the plasmas can have serious effects on density measurements that probe a single rotational level, as well as on reaction rate constants and interpretation of density gradients. The effects of water-cooling the electrodes and the presence of a silicon wafer on temperature were also measured

Containment of high temperature plasmas

International Nuclear Information System (INIS)

Bass, R.W.; Ferguson, H.R.P.; Fletcher, H. Jr.; Gardner, J.; Harrison, B.K.; Larsen, K.M.

1973-01-01

Apparatus is described for confining a high temperature plasma which comprises: 1) envelope means shaped to form a toroidal hollow chamber containing a plasma, 2) magnetic field line generating means for confining the plasma in a smooth toroidal shape without cusps. (R.L.)

Measurement of core plasma temperature and rotation on W7-X made available by the x-ray imaging crystal spectrometer (XICS)

Energy Technology Data Exchange (ETDEWEB)

Pablant, N A; Bitter, M; Burhenn, R; Delgado-Aparicio, L; Ellis, R; Gates, D; Goto, M; Hill, K W; Langenberg, A; Lazerson, S; Mardenfeld, M; Morita, S; Neilson, G H; Oishi, T; Pedersen, T S

2014-07-01

A new x-ray imaging crystal spectrometer diagnostic (XICS) is currently being built for installation on W7-X. This diagnostic will contribute to the study of ion and electron thermal transport and the evolution of the radial electric field by providing high resolution temperature and rotation measurements under many plasma conditions, including ECH heated plasmas. Installation is expected before the first experimental campaign (OP1.1), making an important set of measurements available for the first W7-X plasmas. This diagnostic will also work in concert with the HR-XCS diagnostic to provide an excellent diagnostic set for core impurity transport on W7-X.

Atomic processes in high temperature plasmas

International Nuclear Information System (INIS)

Hahn, Y.

1990-03-01

Much theoretical and experimental efforts have been expended in recent years to study those atomic processes which are specially relevant to understanding high temperature laboratory plasmas. For magnetically confined fusion plasmas, the temperature range of interest spans from the hundreds of eV at plasma edges to 10 keV at the center of the plasma, where most of the impurity ions are nearly fully ionized. These highly stripped ions interact strongly with electrons in the plasma, leading to further excitation and ionization of the ions, as well as electron capture. Radiations are emitted during these processes, which easily escape to plasma container walls, thus cooling the plasma. One of the dominant modes of radiation emission has been identified with dielectronic recombination. This paper reviews this work

X-ray spectroscopic study of high-temperature plasmas by curved crystal spectrometer

International Nuclear Information System (INIS)

Morita, Shigeru.

1983-07-01

Extensive studies have been carried out on the structure of X-ray spectra from the highly stripped ions of first transition elements and their behavior in high temperature plasma, using a high resolution crystal spectrometer. Calculation was made on the design and the use of a curved crystal spectrometer for plasma diagnostics. A Johann type crystal spectrometer for measuring X-ray lines was constructed on the basis of the calculation. The characteristics of curved crystals of LiF, Ge and quartz used for the measurement of Kα lines from first transition elements were investigated. Vacuum sparks have been formed for producing high temperature plasma which emits X-ray lines from highly stripped ions. Two different structures of vacuum spark plasma were shown, that is, thermalized point plasma and extended plasma associated with non-thermal electrons. The X-ray lines from the extended plasma, those associated with the K shell from the point plasma and the Kα lines of Ti through Zn from the point plasma have been observed. (Kako, I.)

The 2017 Plasma Roadmap: Low temperature plasma science and technology

Science.gov (United States)

Adamovich, I.; Baalrud, S. D.; Bogaerts, A.; Bruggeman, P. J.; Cappelli, M.; Colombo, V.; Czarnetzki, U.; Ebert, U.; Eden, J. G.; Favia, P.; Graves, D. B.; Hamaguchi, S.; Hieftje, G.; Hori, M.; Kaganovich, I. D.; Kortshagen, U.; Kushner, M. J.; Mason, N. J.; Mazouffre, S.; Mededovic Thagard, S.; Metelmann, H.-R.; Mizuno, A.; Moreau, E.; Murphy, A. B.; Niemira, B. A.; Oehrlein, G. S.; Petrovic, Z. Lj; Pitchford, L. C.; Pu, Y.-K.; Rauf, S.; Sakai, O.; Samukawa, S.; Starikovskaia, S.; Tennyson, J.; Terashima, K.; Turner, M. M.; van de Sanden, M. C. M.; Vardelle, A.

2017-08-01

Journal of Physics D: Applied Physics published the first Plasma Roadmap in 2012 consisting of the individual perspectives of 16 leading experts in the various sub-fields of low temperature plasma science and technology. The 2017 Plasma Roadmap is the first update of a planned series of periodic updates of the Plasma Roadmap. The continuously growing interdisciplinary nature of the low temperature plasma field and its equally broad range of applications are making it increasingly difficult to identify major challenges that encompass all of the many sub-fields and applications. This intellectual diversity is ultimately a strength of the field. The current state of the art for the 19 sub-fields addressed in this roadmap demonstrates the enviable track record of the low temperature plasma field in the development of plasmas as an enabling technology for a vast range of technologies that underpin our modern society. At the same time, the many important scientific and technological challenges shared in this roadmap show that the path forward is not only scientifically rich but has the potential to make wide and far reaching contributions to many societal challenges.

The 2017 Plasma Roadmap: Low temperature plasma science and technology

International Nuclear Information System (INIS)

Adamovich, I; Baalrud, S D; Bogaerts, A; Bruggeman, P J; Cappelli, M; Colombo, V; Czarnetzki, U; Ebert, U; Eden, J G; Favia, P; Graves, D B; Hamaguchi, S; Hieftje, G; Hori, M

2017-01-01

Journal of Physics D: Applied Physics published the first Plasma Roadmap in 2012 consisting of the individual perspectives of 16 leading experts in the various sub-fields of low temperature plasma science and technology. The 2017 Plasma Roadmap is the first update of a planned series of periodic updates of the Plasma Roadmap. The continuously growing interdisciplinary nature of the low temperature plasma field and its equally broad range of applications are making it increasingly difficult to identify major challenges that encompass all of the many sub-fields and applications. This intellectual diversity is ultimately a strength of the field. The current state of the art for the 19 sub-fields addressed in this roadmap demonstrates the enviable track record of the low temperature plasma field in the development of plasmas as an enabling technology for a vast range of technologies that underpin our modern society. At the same time, the many important scientific and technological challenges shared in this roadmap show that the path forward is not only scientifically rich but has the potential to make wide and far reaching contributions to many societal challenges. (topical review)

Electron temperature measurements inside the ablating plasma of gas-filled hohlraums at the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Barrios, M. A.; Liedahl, D. A.; Schneider, M. B.; Jones, O.; Brown, G. V.; Fournier, K. B.; Moore, A. S.; Ross, J. S.; Landen, O.; Kauffman, R. L.; Nikroo, A.; Kroll, J.; Callahan, D. A.; Hinkel, D. E.; Bradley, D.; Moody, J. D. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Regan, S. P. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States); Jaquez, J.; Huang, H. [General Atomics, San Diego, California 92121 (United States); Hansen, S. B. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)

2016-05-15

The first measurement of the electron temperature (T{sub e}) inside a National Ignition Facility hohlraum is obtained using temporally resolved K-shell X-ray spectroscopy of a mid-Z tracer dot. Both isoelectronic- and interstage-line ratios are used to calculate the local T{sub e} via the collisional–radiative atomic physics code SCRAM [Hansen et al., High Energy Density Phys 3, 109 (2007)]. The trajectory of the mid-Z dot as it is ablated from the capsule surface and moves toward the laser entrance hole (LEH) is measured using side-on x-ray imaging, characterizing the plasma flow of the ablating capsule. Data show that the measured dot location is farther away from the LEH in comparison to the radiation-hydrodynamics simulation prediction using HYDRA [Marinak et al., Phys. Plasmas 3, 2070 (1996)]. To account for this discrepancy, the predicted simulation T{sub e} is evaluated at the measured dot trajectory. The peak T{sub e}, measured to be 4.2 keV ± 0.2 keV, is ∼0.5 keV hotter than the simulation prediction.

Damping Measurements of Plasma Modes

Science.gov (United States)

Anderegg, F.; Affolter, M.; Driscoll, C. F.

2010-11-01

For azimuthally symmetric plasma modes in a magnesium ion plasma, confined in a 3 Tesla Penning-Malmberg trap with a density of n ˜10^7cm-3, we measure a damping rate of 2s-1plasma column, alters the frequency of the mode from 16 KHz to 192 KHz. The oscillatory fluid displacement is small compared to the wavelength of the mode; in contrast, the fluid velocity, δvf, can be large compared to v. The real part of the frequency satisfies a linear dispersion relation. In long thin plasmas (α> 10) these modes are Trivelpiece-Gould (TG) modes, and for smaller values of α they are Dubin spheroidal modes. However the damping appears to be non-linear; initially large waves have weaker exponential damping, which is not yet understood. Recent theoryootnotetextM.W. Anderson and T.M. O'Neil, Phys. Plasmas 14, 112110 (2007). calculates the damping of TG modes expected from viscosity due to ion-ion collisions; but the measured damping, while having a similar temperature and density dependence, is about 40 times larger than calculated. This discrepancy might be due to an external damping mechanism.

13th TOPICAL CONFERENCE ON HIGH TEMPERATURE PLASMA DIAGNOSTICS SCIENTIFIC PROGRAM

Energy Technology Data Exchange (ETDEWEB)

C. BARNES

2000-07-01

Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either overdense, operating at high density relative to the magnetic field (e.g. {omega}{sub pe} >> {Omega}{sub ce} in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition ({tau} > 2). Electron Bernstein waves (EBWs) are electrostatic waves which can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers, as a result of their large K{sub i}. This talk reports on measurements of EBW emission on the CDX-U spherical torus, where B{sub 0} {approx} 2 kG, {approx} 10{sup 13} cm{sup -3} and T{sub e} {approx} 10 - 200 eV. Results will be presented for both direct detection of EBWs and for mode-converted EBW emission. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multi-point Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be {le} T{sub e} and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe was employed to measure changes in edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Changes in the mode conversion efficiency may explain the observation of mode-converted EBW radiation temperatures below T{sub e}. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where {omega}{sub pe} >> {Omega}{sub ce}.

Temperature measurements in ZT-40M

International Nuclear Information System (INIS)

Little, E.M.; Haberstich, A.; Thomas, K.S.; Watt, R.G.

1983-01-01

Electron temperatures derived from Thomson scattering and ultrasoft x-ray (USXR) measurements taken before and after machine modifications are compared for ZT-40M. Modifications were made to the magnetic field windings to reduce field errors and the joints in the aluminum shell were coated with joint compound to reduce resistance and make all joints electrically uniform. These modifications resulted in increased plasma lifetime in ZT-40M from less than 10 ms to over 20 ms. Thomson scattering measurements were made with a single-point Thomson scattering apparatus. The scattered spectrum is collected by a three-grating spectrometer. The soft x rays are collected by a two-foil differential transmission system whose foil ratios may be easily varied. Before modifications the Thomson scattering and soft x-ray temperatures agreed up until 3 to 4 ms into the discharge. After this time the Thomson scattering temperature decreased slowly while the soft x-ray ''temperature'' increased rapidly. field errors resulted in Thomson scattering and USXR ''temperature'' time histories remaining fairly flat out to 10 to 11 ms, but introduced a small discrepancy (about 50 eV) in the absolute value of the temperatures. This change may be due either to the change in foil thickness used or to changes in radial temperature profiles. Profile changes may have been caused by the addition of four poloidal limiters or improvements to the magnetic field topology. After modifications the temperatures from both Thomson scattering and USXR were lower and the plasma density was higher. This is probably a result of the lower plasma-wall interaction with the new configuration

Measurements of plasma rotation in an axially magnetized MPD arc-jet

Energy Technology Data Exchange (ETDEWEB)

Tobari, Hiroyuki; Ashino, Masashi; Yoshino, Kyohei; Sagi, Yukiko; Yoshinuma, Mikirou; Hattori, Kunihiko; Ando, Akira; Inutake, Masaaki [Department of Electrical Engineering, Graduate School of Engineering, Tohoku University, Sendai, Miyagi (Japan)

2001-01-24

Characteristics of an axially magnetized MPD (magneto-plasma-dynamic) arcjet plasma are investigated by spectroscopy on the HITOP (High density of Tohoku Plasma) device in Tohoku University. Plasma flow and rotational velocity and temperature of He ion and atom near the muzzle region of MPD arcjet are measured by Doppler shift and broadening of the HeI ({lambda}=578.56 nm) and HeII ({lambda}=468.58 nm) lines. From the measured radial profile of rotational velocity and temperature of He ion, the radial profiles of electrical field and space potential are calculated and it has been found that the potential profile in the core region is parabolic, which shows the plasma rotates as a rigid body. (author)

Low-temperature plasma modelling and simulation

NARCIS (Netherlands)

Dijk, van J.

2011-01-01

Since its inception in the beginning of the twentieth century, low-temperature plasma science has become a major ¿eld of science. Low-temperature plasma sources and gas discharges are found in domestic, industrial, atmospheric and extra-terrestrial settings. Examples of domestic discharges are those

Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas

Energy Technology Data Exchange (ETDEWEB)

Goel, A., E-mail: ashish09@stanford.edu; Tarantino, P. M.; Lauben, D. S.; Close, S. [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States)

2015-04-15

An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments.

Low temperature plasma technology methods and applications

CERN Document Server

Chu, Paul K

2013-01-01

Written by a team of pioneering scientists from around the world, Low Temperature Plasma Technology: Methods and Applications brings together recent technological advances and research in the rapidly growing field of low temperature plasmas. The book provides a comprehensive overview of related phenomena such as plasma bullets, plasma penetration into biofilms, discharge-mode transition of atmospheric pressure plasmas, and self-organization of microdischarges. It describes relevant technology and diagnostics, including nanosecond pulsed discharge, cavity ringdown spectroscopy, and laser-induce

Measurements of Relativistic Effects in Collective Thomson Scattering at Electron Temperatures less than 1 keV

Energy Technology Data Exchange (ETDEWEB)

Ross, James Steven [Univ. of California, San Diego, CA (United States)

2010-01-01

Simultaneous scattering from electron-plasma waves and ion-acoustic waves is used to measure local laser-produced plasma parameters with high spatiotemporal resolution including electron temperature and density, average charge state, plasma flow velocity, and ion temperature. In addition, the first measurements of relativistic modifications in the collective Thomson scattering spectrum from thermal electron-plasma fluctuations are presented [1]. Due to the high phase velocity of electron-plasma fluctuations, relativistic effects are important even at low electron temperatures (T_e < 1 keV). These effects have been observed experimentally and agree well with a relativistic treatment of the Thomson scattering form factor [2]. The results are important for the interpretation of scattering measurements from laser produced plasmas. Thomson scattering measurements are used to characterize the hydrodynamics of a gas jet plasma which is the foundation for a broad series of laser-plasma interaction studies [3, 4, 5, 6]. The temporal evolution of the electron temperature, density and ion temperature are measured. The measured electron density evolution shows excellent agreement with a simple adiabatic expansion model. The effects of high temperatures on coupling to hohlraum targets is discussed [7]. A peak electron temperature of 12 keV at a density of 4.7 × 10²⁰cm^-3 are measured 200 μm outside the laser entrance hole using a two-color Thomson scattering method we developed in gas jet plasmas [8]. These measurements are used to assess laser-plasma interactions that reduce laser hohlraum coupling and can significantly reduce the hohlraum radiation temperature.

3.5. Apparatus for plasma electron temperature measurement by Thomson scattering

International Nuclear Information System (INIS)

Kolacek, K.; Babicky, V.

1981-01-01

Equipment was developed and tested for measuring time-resolved local electron plasma temperature and density by the Thomson scattering of ruby laser light. The laser consists of a Q-switched generator (ruby 12 mm in diameter by 150 mm long) followed by one amplifier (ruby 16 mm indi long) followed by one amplifier (ruby 16 mm in diameter by 250 mm long). For Q-switching a Pockels cell with a z-cut ADP crystal was used. The laser is capable of delivering 4 J of energy in a pulse of 50 ns in duration. The spectrum of the laser light scattered at an angle of 9a degrees is analyzed by a six-channel polychromator. Fibre optics and photomultipliers with gated amplifiers are used. Output signals are transmitted via a parallel-to-series converter to a single-trace oscilloscope. The whole Thomson scattering apparatus was successfully tested by the Rayleigh scattering in the air at atmospheric pressure. (J.U.)

Temperature diagnostics of a non-thermal plasma jet at atmospheric pressure

Science.gov (United States)

Schäfer, Jan

2013-09-01

The study reflects the concept of the temperature as a physical quantity resulting from the second thermodynamic law. The reliability of different approaches of the temperature diagnostics of open non-equilibrium systems is discussed using examples of low temperature atmospheric pressure discharges. The focus of this work is a miniaturized non-thermal atmospheric pressure plasma jet for local surface treatment at ambient atmosphere. The micro-discharge is driven with a capacitively coupled radio frequency electric field at 27.12 MHz and fed with argon at rates of about 1 slm through the capillary with an inner diameter of 4 mm. The discharge consists of several contracted filaments with diameter around 300 μm which are rotating azimuthally in the capillary in a self-organized manner. While the measured temperatures of the filament core exceed 700 K, the heat impact on a target below the plasma jet remains limited leading to target temperatures below 400 K. Different kinds of temperatures and energy transport processes are proposed and experimentally investigated. Nevertheless, a reliable and detailed temperature diagnostics is a challenge. We report on a novel diagnostics approach for the spatially and temporally resolved measurement of the gas temperature based on the optical properties of the plasma. Laser Schlieren Deflectometry is adapted to explore temperature profiles of filaments and their behaviour. In parallel, the method demonstrates a fundamental Fermat's principle of minimal energy. Information acquired with this method plays an important role for the optimization of local thin film deposition and surface functionalization by means of the atmospheric pressure plasma jet. The work was supported in part by the Deutsche Forschungsgemeinschaft within SFB-TR 24.

Constituent Ion Temperatures Measured in the Topside Ionosphere

Science.gov (United States)

Hsu, C. T.; Heelis, R. A.

2017-12-01

Plasma temperatures in the ionosphere are associated with both the dynamics and structure of the neutral and charge particles. The temperatures are determined by solar energy inputs and energy exchange between charged particles and neutrals. Previous observations show that during daytime the O+ temperature is generally higher when the fractional contribution of H+ to the plasma is high. Further simulations confirm that the daytime heat balance between the H+ and O+ always keeps the H+ at a temperature higher than the O+. In addition the plasma transport parallel and perpendicular to the magnetic field influences the plasma temperature through adiabatic heating and cooling effects. These processes are also important during the nighttime, when the source of photoionization is absent. In this work we examine a more sophisticated analysis procedure to extract individual mass dependent ion temperature and apply it on the DMSP F15 RPA measurements. The result shows that the daytime TH+ is a few hundred degrees higher than the TO+ and the nighttime temperature difference between TH+ and TO+ is indicative of mass dependent adiabatic heating and cooling processes across the equatorial region.

Determination of plasma temperature and electron density in river sediment plasma using calibration-free laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Austria, Elmer S. Jr.; Lamorena-Lim, Rheo B.

2015-01-01

Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique is an approach used to quantitatively measure elemental composition of samples without the use of standard reference materials (SRMs). Due to the unavailability of most SRMs for specific samples, the CF-LIBS approach is steadily becoming more prevalent. CF-LIBS also minimizes interferences from the sample matrix by accounting spectral line intensifies of different elements. The first part of the CF-LIBS algorithm is the calculation of plasma temperature and electron density of the sample while the second part deals with the self-absorption correction and quantitative elemental analysis. In this study, the precursor parameters for the algorithm - plasma temperature and electron density - were measured through the neutral atom and ion line emissions of Fe and Cu in the time window of 0.1 to 10 μs. Plasma from river sediment samples were produced by a 1064 nm nanosecond pulsed Nd:YAG laser at atmospheric pressure. The plasma temperature and electron density were calculated from the Boltzmann plot and Saha-Boltzmann equation methods, respectively. These precursor parameters can be used in calculating the time window wherein the plasma is optically thin at local thermodynamic equilibrium (LTE) and for quantitative multi-elemental analysis. (author)

High-speed three-dimensional plasma temperature determination of axially symmetric free-burning arcs

International Nuclear Information System (INIS)

Bachmann, B; Ekkert, K; Bachmann, J-P; Marques, J-L; Schein, J; Kozakov, R; Gött, G; Schöpp, H; Uhrlandt, D

2013-01-01

In this paper we introduce an experimental technique that allows for high-speed, three-dimensional determination of electron density and temperature in axially symmetric free-burning arcs. Optical filters with narrow spectral bands of 487.5–488.5 nm and 689–699 nm are utilized to gain two-dimensional spectral information of a free-burning argon tungsten inert gas arc. A setup of mirrors allows one to image identical arc sections of the two spectral bands onto a single camera chip. Two-different Abel inversion algorithms have been developed to reconstruct the original radial distribution of emission coefficients detected with each spectral window and to confirm the results. With the assumption of local thermodynamic equilibrium we calculate emission coefficients as a function of temperature by application of the Saha equation, the ideal gas law, the quasineutral gas condition and the NIST compilation of spectral lines. Ratios of calculated emission coefficients are compared with measured ones yielding local plasma temperatures. In the case of axial symmetry the three-dimensional plasma temperature distributions have been determined at dc currents of 100, 125, 150 and 200 A yielding temperatures up to 20000 K in the hot cathode region. These measurements have been validated by four different techniques utilizing a high-resolution spectrometer at different positions in the plasma. Plasma temperatures show good agreement throughout the different methods. Additionally spatially resolved transient plasma temperatures have been measured of a dc pulsed process employing a high-speed frame rate of 33000 frames per second showing the modulation of the arc isothermals with time and providing information about the sensitivity of the experimental approach. (paper)

Precise measurements of neutral gas temperature using Fiber Bragg Grating sensor in Argon capacitively coupled plasmas

Science.gov (United States)

Han, Daoman; Liu, Zigeng; Liu, Yongxin; Peng, Wei; Wang, Younian

2016-09-01

Neutral gas temperature was measured using Fiber Bragg Grating sensor (FBGs) in capacitively coupled argon plasmas. Thermometry is based on the thermal equilibrium between the sensor and neutral gases, which is found to become faster with increasing pressure. It is also observed that the neutral gas temperature is higher than the room temperature by 10 120 °depending on the experiental conditions, and gas temperature shows significant non-uniformity in space. In addition, radial profiles of neutral temperature at different pressures, resemble these of ion density, obtained by a floating double probe. Specifically, at low pressure, neutral gas temperature and ion density peak at the center of the reactor, while the peak appears at the edge of the electrode at higher pressure. The neutral gas heating is mainly caused by the elastic collisions of Ar + with neutral gas atoms in the sheath region after Ar + gaining a certain energy. This work was supported by the National Natural Science Foundation of China (NSFC) (Grants No. 11335004, 11405018, and 61137005).

Kinetics and spectroscopy of low temperature plasmas

CERN Document Server

Loureiro, Jorge

2016-01-01

This is a comprehensive textbook designed for graduate and advanced undergraduate students. Both authors rely on more than 20 years of teaching experience in renowned Physics Engineering courses to write this book addressing the students’ needs. Kinetics and Spectroscopy of Low Temperature Plasmas derives in a full self-consistent way the electron kinetic theory used to describe low temperature plasmas created in the laboratory with an electrical discharge, and presents the main optical spectroscopic diagnostics used to characterize such plasmas. The chapters with the theoretical contents make use of a deductive approach in which the electron kinetic theory applied to plasmas with basis on the electron Boltzmann equation is derived from the basic concepts of Statistical and Plasma Physics. On the other hand, the main optical spectroscopy diagnostics used to characterize experimentally such plasmas are presented and justified from the point of view of the Atomic and Molecular Physics. Low temperature plasmas...

Integrated discharge scenario for high-temperature helical plasma on LHD

International Nuclear Information System (INIS)

Nagaoka, K.; Takahashi, H.; Murakami, S.

2014-10-01

Discharge scenario of high temperature plasma with helical configuration has been significantly progressed. The increase of central ion temperature due to reduction of wall recycling was clearly observed. The neutral particle profile was measured with a high-dynamic range of Balmer-α spectroscopy, and the reduction of neutral density was identified after helium conditioning main discharges. The peaking of ion heating profile and the reduction of charge exchange loss of energetic ions play an important role for improvement of ion heat transport in the core. The ion ITB and electron ITB have been successfully integrated due to superposition of centrally focused electron cyclotron heating to the ion ITB plasma, and the high temperature regime of T i ∼T e has been significantly extended. The normalized temperature gradient of ion and electron (R/L T ) were observed to exceed 10, indicating the significant improvement of both ion and electron heat transports at the barrier position. The positive radial electric field was observed by heavy ion beam probe, while the negative radial electric field was observed in ion ITB plasmas. The ion temperature gradient was observed to decrease with the increase of temperature ratio (T e /T i ). This experiment demonstrated that the profile control is a key to combine ion ITB and electron ITB and have a potential to improve the performance of helical plasmas. (author)

Effect of morning bright light on body temperature, plasma cortisol and wrist motility measured during 24 hour of constant conditions.

Science.gov (United States)

Foret, J; Aguirre, A; Touitou, Y; Clodoré, M; Benoit, O

1993-06-11

Using 24 h constant conditions, time course of body temperature, plasma cortisol and wrist motility was measured in response to a 3 day morning 2 h bright light pulse. This protocol demonstrated that a 2000 lux illumination was sufficient to elicit a shift of about 2 h of temperature minimum and cortisol peak. In reference session, actimetric recordings showed a circadian time course, closely in relation with core temperature. Bright light pulse resulted in a decrease of amplitude and a disappearance of circadian pattern of actimetry.

Evolution of the electron temperature profile of ohmically heated plasmas in TFTR

International Nuclear Information System (INIS)

Taylor, G.; Efthimion, P.C.; Arunasalam, V.

1985-08-01

Blackbody electron cyclotron emission was used to ascertain and study the evolution and behavior of the electron temperature profile in ohmically heated plasmas in the Tokamak Fusion Test Reactor (TFTR). The emission was measured with absolutely calibrated millimeter wavelength radiometers. The temperature profile normalized to the central temperature and minor radius is observed to broaden substantially with decreasing limiter safety factor q/sub a/, and is insensitive to the plasma minor radius. Sawtooth activity was seen in the core of most TFTR discharges and appeared to be associated with a flattening of the electron temperature profile within the plasma core where q less than or equal to 1. Two types of sawtooth behavior were identified in large TFTR plasmas (minor radius, a less than or equal to 0.8 m) : a typically 35 to 40 msec period ''normal'' sawtooth, and a ''compound'' sawtooth with 70 to 80 msec period

High temperature divertor plasma operation

International Nuclear Information System (INIS)

Ohyabu, Nobuyoshi.

1991-02-01

High temperature divertor plasma operation has been proposed, which is expected to enhance the core energy confinement and eliminates the heat removal problem. In this approach, the heat flux is guided through divertor channel to a remote area with a large target surface, resulting in low heat load on the target plate. This allows pumping of the particles escaping from the core and hence maintaining of the high divertor temperature, which is comparable to the core temperature. The energy confinement is then determined by the diffusion coefficient of the core plasma, which has been observed to be much lower than the thermal diffusivity. (author)

Nanoparticle manipulation in the near-substrate areas of low-temperature, high-density rf plasmas

International Nuclear Information System (INIS)

Rutkevych, P.P.; Ostrikov, K.; Xu, S.

2005-01-01

Manipulation of a single nanoparticle in the near-substrate areas of high-density plasmas of low-temperature glow discharges is studied. It is shown that the nanoparticles can be efficiently manipulated by the thermophoretic force controlled by external heating of the substrate stage. Particle deposition onto or repulsion from nanostructured carbon surfaces critically depends on the values of the neutral gas temperature gradient in the near-substrate areas, which is directly measured in situ in different heating regimes by originally developed temperature gradient probe. The measured values of the near-surface temperature gradient are used in the numerical model of nanoparticle dynamics in a variable-length presheath. Specific conditions enabling the nanoparticle to overcome the repulsive potential and deposit on the substrate during the discharge operation are investigated. The results are relevant to fabrication of various nanostructured films employing structural incorporation of the plasma-grown nanoparticles, in particular, to nanoparticle deposition in the plasma-enhanced chemical-vapor deposition of carbon nanostructures in hydrocarbon-based plasmas

Behavior of 23S metastable state He atoms in low-temperature recombining plasmas

Science.gov (United States)

Kajita, Shin; Tsujihara, Tadashi; Aramaki, Mitsutoshi; van der Meiden, Hennie; Oshima, Hiroshi; Ohno, Noriyasu; Tanaka, Hirohiko; Yasuhara, Ryo; Akiyama, Tsuyoshi; Fujii, Keisuke; Shikama, Taiichi

2017-07-01

We measured the electron density and temperature using laser Thomson scattering and metastable state (23S) of He atoms by laser absorption spectroscopy in the detached recombining plasmas in the divertor simulator NAGDIS-II. Using the measured electron density and temperature combined with the particle trajectory trace simulation, we discussed the behavior of the metastable state He atoms based on comparisons with the experimental results. It is shown that the metastable state atoms are mainly produced in the peripheral region of the plasma column, where the temperature is lower than the central part, and diffused in the vacuum vessel. It was shown that the 0D model is not valid and the transport of the metastable states is to be taken into account for the population distribution of He atoms in the detached plasmas.

Ion emission from laser-produced plasmas with two electron temperatures

International Nuclear Information System (INIS)

Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

1978-01-01

An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

Estimation of post disruption plasma temperature for fast current quench Aditya plasma shots

International Nuclear Information System (INIS)

Purohit, S.; Chowdhuri, M.B.; Joisa, Y.S.; Raval, J.V.; Ghosh, J.; Jha, R.

2013-01-01

Characteristics of tokamak current quenches are an important issue for the determination of electromagnetic forces that act on the in-vessel components and vacuum vessel during major disruptions. It is observed that thermal quench is followed by a sharp current decay. Fast current quench disruptive plasma shots were investigated for ADITYA tokamak. The current decay time was determined for the selected shots, which were in the range of 0.8 msec to 2.5 msec. This current decay information was then applied to L/R model, frequently employed for the estimation of the current decay time in tokamak plasmas, considering plasma inductance and plasma resistivity. This methodology was adopted for the estimation of the post disruption plasma temperature using the experimentally observed current decay time for the fast current quench disruptive ADITYA plasma shots. The study reveals that for the identified shots there is a constant increase in the current decay time with the post disruption plasma temperature. The investigations also explore the behavior post disruption plasma temperature and the current decay time as a function of the edge safety factor, Q. Post disruption plasma temperature and the current decay time exhibits a decrease with the increase in the value Q. (author)

On methods of measuring the relative plasma composition by active charge exchange

International Nuclear Information System (INIS)

Herrmann, W.

1991-04-01

Two methods of measuring the hydrogenic composition of plasma with an active diagnostic beam are discussed: Evaluation at equal energies of the neutrals leaving the plasma and at equal velocities. Evaluation at equal velocity has the advantage that the plasma composition, particle penetration and stripping efficiency of the analyzer do not enter the evaluation. The only plasma parameter that has to be known is the plasma temperature. If measurement at two different velocities is possible, the temperature can also be evaluated from the corresponding four fluxes without any further knowledge of plasma or beam parameters. It is discussed under what circumstances evaluation of the plasma composition is possible for non-Maxwellian distribution functions. As the halo effect may be the main source of error, it is shown that the application of a helium beam may considerably reduce this problem. (orig.)

Determination of the time evolution of the electron-temperature profile of reactor-like plasmas from the measurement of blackbody electron-cyclotron emission

International Nuclear Information System (INIS)

Efthimion, P.C.; Arunasalam, V.; Bitzer, R.A.; Hosea, J.C.

1982-04-01

Plasma characteristics (i.e., n/sub e/ greater than or equal to 1 x 10 13 cm -3 , T/sub e/ greater than or equal to 10 7 0 K, B/sub psi/ greater than or equal to 20 kG) in present and future magnetically confined plasma devices, e.g., Princeton Large Torus (PLT) and Tokamak Fusion Test Reactor (TFTR), meet the conditions for blackbody emission near the electron cyclotron frequency and at few harmonics. These conditions, derived from the hot plasma dielectric tensor, have been verified by propagation experiments on PLT and the Princeton Model-C Stellarator. Blackbody emission near the fundamental electron cyclotron frequency and the second harmonic have been observed in PLT and is routinely measured to ascertain the time evolution of the electron temperature profile. These measurements are especially valuable in the study of auxiliary heating of tokamak plasma. Measurement and calibration techniques will also be discussed with special emphasis on our fast-scanning heterodyne receiver concept

A compact new incoherent Thomson scattering diagnostic for low-temperature plasma studies

Science.gov (United States)

Vincent, Benjamin; Tsikata, Sedina; Mazouffre, Stéphane; Minea, Tiberiu; Fils, Jérôme

2018-05-01

Incoherent Thomson scattering (ITS) has a long history of application for the determination of electron density and temperature in dense fusion plasmas, and in recent years, has been increasingly extended to studies in low-temperature plasma environments. In this work, the design and preliminary implementation of a new, sensitive and uniquely compact ITS platform known as Thomson scattering experiments for low temperature ion sources are described. Measurements have been performed on a hollow cathode plasma source, providing access to electron densities as low as 1016 m‑3 and electron temperatures of a few eV and below. This achievement has been made possible by the implementation of a narrow volume Bragg grating notch filter for the attenuation of stray light, a feature which guarantees compactness and reduced transmission losses in comparison to standard ITS platforms.

Measurement of plasma edge profile on Wendelstein 7-X

Energy Technology Data Exchange (ETDEWEB)

Drews, Philipp; Liang, Yunfeng; Neubauer, Olaf; Denner, Peter; Rack, Michael; Liu, Shaocheng; Wang, Nunchao; Nicolai, Dirk; Hollfeld, Klaus; Satheeswaran, Guruparan [Forschungszentrum Juelich, IEK4, Juelich (Germany); Grulke, Olaf [Max-Planck-Institut fuer Plasmaphysik, Greifswald (Germany); Collaboration: W7-X Team

2016-07-01

Wendelstein 7-X (W7-X), currently under commissioning at the IPP Greifswald, will be the world's largest stellarator with modular superconducting coils, which will enable steady-state-like plasma operation of up to thirty minutes in order to explore the reactor relevance of this concept. The first operation phase of W7-X will employ a limiter configuration. It will be used primarily for setting up the diagnostics and testing the magnetic configuration. In conjunction with the multipurpose manipulator, a fast reciprocating probe is installed. The combined probe head will be used to measure the radial distribution of the magnetic field using magnetic pick-up coils; the plasma temperature and density profiles and the radial electric field using Langmuir pins; and the plasma flows using a Mach setup. As a quasi-isodynamic stellarator, it has been predicted that not only neoclassical but also turbulent transport will be comparable to or possibly even lower than that of tokamaks. Edge plasma profile measurements, especially those of the electron temperature and density, will play a key role in validating this performance in comparison to the tokamak and hence the viability of a stellarator fusion reactor. The edge plasma profile measurements using the combined probe head are presented.

Criteria governing electron plasma waves in a two-temperature plasma

International Nuclear Information System (INIS)

Dell, M.P.; Gledhill, I.M.A.; Hellberg, M.A.

1987-01-01

Using a technique based on the saddle-points of the dielectric function, criteria are found which govern the behaviour of electron plasma waves in plasmas with two electron populations having different temperatures. (orig.)

Measurements of long-range enhanced collisional velocity drag through plasma wave damping

Science.gov (United States)

Affolter, M.; Anderegg, F.; Dubin, D. H. E.; Driscoll, C. F.

2018-05-01

We present damping measurements of axial plasma waves in magnetized, multispecies ion plasmas. At high temperatures T ≳ 10-2 eV, collisionless Landau damping dominates, whereas, at lower temperatures T ≲ 10-2 eV, the damping arises from interspecies collisional drag, which is dependent on the plasma composition and scales roughly as T-3 /2 . This drag damping is proportional to the rate of parallel collisional slowing, and is found to exceed classical predictions of collisional drag damping by as much as an order of magnitude, but agrees with a new collision theory that includes long-range collisions. Centrifugal mass separation and collisional locking of the species occur at ultra-low temperatures T ≲ 10-3 eV, which reduce the drag damping from the T-3 /2 collisional scaling. These mechanisms are investigated by measuring the damping of higher frequency axial modes, and by measuring the damping in plasmas with a non-equilibrium species profile.

Temperature measurement of plasma-assisted flames: comparison between optical emission spectroscopy and 2-color laser induced fluorescence techniques

KAUST Repository

Lacoste, Deanna A.

2015-03-30

Accurate thermometry of highly reactive environments, such as plasma-assisted combustion, is challenging. With the help of conical laminar premixed methane-air flames, this study compares two thermometry techniques for the temperature determination in a combustion front enhanced by nanosecond repetitively pulsed (NRP) plasma discharges. Based on emission spectroscopic analysis, the results show that the rotational temperature of CH(A) gives a reasonable estimate for the adiabatic flame temperature, only for lean and stoichiometric conditions. The rotational temperature of N2(C) is found to significantly underestimate the flame temperature. The 2-color OH-PLIF technique gives correct values of the flame temperature.

Temperature measurement of plasma-assisted flames: comparison between optical emission spectroscopy and 2-color laser induced fluorescence techniques

KAUST Repository

Lacoste, Deanna A.; Heitz, Sylvain A.; Moeck, Jonas P.

2015-01-01

Accurate thermometry of highly reactive environments, such as plasma-assisted combustion, is challenging. With the help of conical laminar premixed methane-air flames, this study compares two thermometry techniques for the temperature determination in a combustion front enhanced by nanosecond repetitively pulsed (NRP) plasma discharges. Based on emission spectroscopic analysis, the results show that the rotational temperature of CH(A) gives a reasonable estimate for the adiabatic flame temperature, only for lean and stoichiometric conditions. The rotational temperature of N2(C) is found to significantly underestimate the flame temperature. The 2-color OH-PLIF technique gives correct values of the flame temperature.

Excitation temperature of a solution plasma during nanoparticle synthesis

Energy Technology Data Exchange (ETDEWEB)

Saito, Genki, E-mail: genki@eng.hokudai.ac.jp; Nakasugi, Yuki; Akiyama, Tomohiro [Center for Advanced Research of Energy and Materials, Hokkaido University, Sapporo 060-8628 (Japan)

2014-08-28

Excitation temperature of a solution plasma was investigated by spectroscopic measurements to control the nanoparticle synthesis. In the experiments, the effects of edge shielding, applied voltage, and electrode material on the plasma were investigated. When the edge of the Ni electrode wire was shielded by a quartz glass tube, the plasma was uniformly generated together with metallic Ni nanoparticles. The emission spectrum of this electrode contained OH, H{sub α}, H{sub β}, Na, O, and Ni lines. Without an edge-shielded electrode, the continuous infrared radiation emitted at the edge created a high temperature on the electrode surface, producing oxidized coarse particles as a result. The excitation temperature was estimated from the Boltzmann plot. When the voltages were varied at the edge-shielded electrode with low average surface temperature by using different electrolyte concentrations, the excitation temperature of current-concentration spots increased with an increase in the voltage. The size of the Ni nanoparticles decreased at high excitation temperatures. Although the formation of nanoparticles via melting and solidification of the electrode surface has been considered in the past, vaporization of the electrode surface could occur at a high excitation temperature to produce small particles. Moreover, we studied the effects of electrodes of Ti, Fe, Ni, Cu, Zn, Zr, Nb, Mo, Pd, Ag, W, Pt, Au, and various alloys of stainless steel and Cu–Ni alloys. With the exception of Ti, the excitation temperatures ranged from 3500 to 5500 K and the particle size depended on both the excitation temperature and electrode-material properties.

Active ion temperature measurement with heating neutral beam

International Nuclear Information System (INIS)

Miura, Yukitoshi; Matsuda, Toshiaki; Yamamoto, Shin

1987-03-01

When the heating neutral-beam (hydrogen beam) is injected into a deuterium plasma, the density of neutral particles is increased locally. By using this increased neutral particles, the local ion temperature is measured by the active charge-exchange method. The analyzer is the E//B type mass-separated neutral particle energy analyzer and the measured position is about one third outside of the plasma radius. The deuterium energy spectrum is Maxwellian, and the temperature is increased from 350 eV to 900 eV during heating. Since the local hydrogen to deuterium density concentration and the density of the heating neutral-beam as well as the ion temperature can be obtained good S/N ratio, the usefulness of this method during neutral-beam heating is confirmed by this experiment. (author)

Measuring the equations of state in a relaxed magnetohydrodynamic plasma

Science.gov (United States)

Kaur, M.; Barbano, L. J.; Suen-Lewis, E. M.; Shrock, J. E.; Light, A. D.; Brown, M. R.; Schaffner, D. A.

2018-01-01

We report measurements of the equations of state of a fully relaxed magnetohydrodynamic (MHD) laboratory plasma. Parcels of magnetized plasma, called Taylor states, are formed in a coaxial magnetized plasma gun, and are allowed to relax and drift into a closed flux conserving volume. Density, ion temperature, and magnetic field are measured as a function of time as the Taylor states compress and heat. The theoretically predicted MHD and double adiabatic equations of state are compared to experimental measurements. We find that the MHD equation of state is inconsistent with our data.

Electron density and temperature determination in a Tokamak plasma using light scattering

International Nuclear Information System (INIS)

Perez-Navarro Gomez, A.; Zurro Hernandez, B.

1976-01-01

A theoretical foundation review for light scattering by plasmas is presented. Furthemore, a review of the experimental methods for electron density and temperature measurements, with spatial and time resolution, is included in a Tokamak plasma using spectral analysis of the scattered radiation. (author) [es

Plasma potential measurements in the edge region of the ISTTOK plasma, using electron emissive probes

International Nuclear Information System (INIS)

Ionita, C.; Balan, P.; Schrittwieser, R.; Cabral, J.A.; Fernandes, H.; Figueiredo, H. F.C.; Varandas, C.

2001-01-01

We have recently started to use electron-emissive probes for direct measurements of the plasma potential and its fluctuations in the edge region of the plasma ring in the tokamak ISTTOK in Lisbon, Portugal. This method is based on the fact that the electron emission current of such a probe is able to compensate electron temperature variations and electron drifts, which can occur in the edge plasma region of magnetized fusion devices, and which are making measurements with cold probes prone to errors. In this contribution we present some of the first results of our investigations in ISTTOK.(author)

Technological uses of low temperature plasmas

International Nuclear Information System (INIS)

Lawton, J.

1975-01-01

Types of low temperature plasma sources considered include; arc discharge, high pressure discharge, low pressure discharge and flame. The problems of uniform heating of a gas are discussed and it is considered that the most reliable technique is the magnetically rotated arc, but expanded discharges of one kind or another are likely to be serious competitors in the future. The uses of low temperature plasma in chemistry and combustion are considered. The potential for plasma chemistry lies with processes in which the reactions occur in the plasma itself or its neighbouring gas phase, including those which require the vaporization of liquefaction of a refractory material and also highly endothermic reactions. The production of thixotropic silica and acetylene are discussed as examples of such reactions. The field of plasma and combustion including; ignition, flame ionization and soot formation, and the MHD generator, is considered. (U.K.)

Electron density and temperature determination in a Tokamak plasma using light scattering

International Nuclear Information System (INIS)

Perez-Navarro Gomerz, A.; Zurro Hernandez, B.

1976-01-01

A theoretical foundation review for light scattering by plasmas is presented. Furthermore, we have included a review of the experimental methods for electron density and temperature measurements, with spatial and time resolution, in a Tokamak plasma using spectral analysis of the scattered radiation. (Author) 13 refs

Temperature and Nitric Oxide Generation in a Pulsed Arc Discharge Plasma

International Nuclear Information System (INIS)

Namihira, T.; Sakai, S.; Matsuda, M.; Wang, D.; Kiyan, T.; Akiyama, H.; Okamoto, K.; Toda, K.

2007-01-01

Nitric oxide (NO) is increasingly being used in medical treatments of high blood pressure, acute respiratory distress syndrome and other illnesses related to the lungs. Currently a NO inhalation system consists of a gas cylinder of N 2 mixed with a high concentration of NO. This arrangement is potentially risky due to the possibility of an accidental leak of NO from the cylinder. The presence of NO in the air leads to the formation of nitric dioxide (NO 2 ), which is toxic to the lungs. Therefore, an on-site generator of NO would be highly desirable for medical doctors to use with patients with lung disease. To develop the NO inhalation system without a gas cylinder, which would include a high concentration of NO, NAMIHIRA et al have recently reported on the production of NO from room air using a pulsed arc discharge. In the present work, the temperature of the pulsed arc discharge plasma used to generate NO was measured to optimize the discharge condition. The results of the temperature measurements showed the temperature of the pulsed arc discharge plasma reached about 10,000 K immediately after discharge initiation and gradually decreased over tens of microseconds. In addition, it was found that NO was formed in a discharge plasma having temperatures higher than 9,000 K and a smaller input energy into the discharge plasma generates NO more efficiently than a larger one

X-ray Heating and Electron Temperature of Laboratory Photoionized Plasmas

Science.gov (United States)

Mancini, Roberto; Lockard, Tom; Mayes, Daniel C.; Loisel, Guillaume; Bailey, James E.; Rochau, Gregory; Abdallah, J.; Golovkin, I.

2018-06-01

In separate experiments performed at the Z facility of Sandia National Laboratories two different samples were employed to produce and characterize photoionized plasmas. One was a gas cell filled with neon, and the other was a thin silicon layer coated with plastic. Both samples were driven by the broadband x-ray flux produced at the collapse of a wire array z-pinch implosion. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the charge state distribution, and the electron temperature was extracted from a Li-like ion level population ratio. To interpret the temperature measurement, we performed Boltzmann kinetics and radiation-hydrodynamic simulations. We found that non-equilibrium atomic physics and the coupling of the radiation flux to the atomic level population kinetics play a critical role in modeling the x-ray heating of photoionized plasmas. In spite of being driven by similar x-ray drives, differences of ionization and charged state distributions in the neon and silicon plasmas are reflected in the plasma heating and observed electron temperatures.This work was sponsored in part by DOE Office of Science Grant DE-SC0014451, and the Z Facility Fundamental Science Program of SNL.

Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

Science.gov (United States)

Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

2008-02-01

We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

Soft x-ray imaging system for measurement of noncircular tokamak plasmas

International Nuclear Information System (INIS)

Fonck, R.J.; Reusch, M.; Jaehnig, K.P.; Hulse, R.; Roney, P.

1986-08-01

A soft x-ray camera and image processing system has been constructed to provide measurements of the internal shape of high temperature tokamak plasmas. The camera consists of a metallic-foil-filtered pinhole aperture and a microchannel plate image intensifier/convertor which produces a visible image for detection by a CCD TV camera. A wide-angle tangential view of the toroidal plasma allows a single compact camera to view the entire plasma cross section. With Be filters 12 to 50 μm thick, the signal from the microchannel plate is produced mostly by nickel L-line emissions which orignate in the hot plasma core. The measured toroidal image is numerically inverted to produce a cross-sectional soft x-ray image of the plasma. Since the internal magnetic flux surfaces are usually isothermal and the nickel emissivity depends strongly on the local electron temperature, the x-ray emission contours reflect the shape of the magnetic surfaces in the plasma interior. Initial results from the PBX tokamak experiment show clear differences in internal plasma shapes for circular and bean-shaped discharges

Active neutral particle diagnostics for high temperature plasma

International Nuclear Information System (INIS)

Tobita, Kenji

1993-01-01

This paper describes experimental studies related to active neutral particle diagnostics in the JT-60 tokamak. Detection efficiencies of a micro-channel plate (MCP), which has widely used in plasma diagnostics, were determined for ions and neutrals. Multi-step processes for a neutral beam is predicted to enhance the beam stopping cross section in a plasma. In order to confirm the predictions, shine-through for a hydrogen and for a helium beam was measured in the JT-60 ohmic plasmas. The measurements for a hydrogen beam resulted in the cross sectional enhancement in the beam stopping. The same experiment using a helium beam indicated that the cross sectional enhancement for helium was much smaller than that for hydrogen at almost same plasma parameters. Ion temperature diagnostic using active beam scattering was developed in data processing technique, in consideration of the device function of a neutral particle analyzer and in estimation of the effect of beam ion component. Fundamental experiments for detecting helium ions in a plasma were performed using two-electron transfer reaction between a helium atomic beam and helium ions, and the energy distribution and the density of the helium ions were determined. These experiments demonstrated promise of the two-electron transfer reaction as an alpha ash detection in a burning plasma. A parasitic neutral efflux accompanied by active beam injection was investigated. (J.P.N.)

Measurement of the ion temperature in a diffuse theta pinch

International Nuclear Information System (INIS)

Kudo, Koichi; Watanabe, Yukio; Ogi, Sukeomi; Sumikawa, Toshio; Akazaki, Masanori

1979-01-01

The Doppler broadening of helium ion spectra was observed, and the ion temperature of theta pinch plasma was obtained. The apparatus for the measurement consists of a spectroscope, a photomultiplier and an oscilloscope. The time variation of initial plasma density was obtained. The doppler broadening of the spectra was observed in case of the plasma density of 2 x 10 13 /cm 3 and 3 x 10 12 /cm 3 . The analyses of the spectra gave the ion temperature. The double temperature distribution was seen. The temperature of the low temperature part was 5 to 9 electron-volt, and that of the high temperature part several hundred electron-volt. The high temperature is caused by the thermalization of particles accelerated by the magnetic piston. The decay of high temperature ions is due to the charge exchange with the neutral particles. The time of the highest temperature corresponds to the time at which the luminescent layer reaches to the central axis. (Kato, T.)

Study of a filter spectrometer in the framework of a new method for measuring the temperature of thermonuclear plasmas by relativistic Thomson scattering

International Nuclear Information System (INIS)

Lasalle, J.

1975-06-01

A new method which greatly simplifies the number of measurements necessary for obtaining the temperature in thermonuclear plasmas, using the relativistic effects of Thomson scattering is presented. A few orders of magnitude are computed for probing the feasibility of such temperature measurements. The data used correspond to magnitudes relating to T.F.R. The characteristics of a filter equipped spectrometer are then defined in view of a double function: separation of the lambda>lambda laser and lambda [fr

Study of heat fluxes on plasma facing components in a tokamak from measurements of temperature by infrared thermography

International Nuclear Information System (INIS)

Daviot, R.

2010-05-01

The goal of this thesis is the development of a method of computation of those heat loads from measurements of temperature by infrared thermography. The research was conducted on three issues arising in current tokamaks but also future ones like ITER: the measurement of temperature on reflecting walls, the determination of thermal properties for deposits observed on the surface of tokamak components and the development of a three-dimensional, non-linear computation of heat loads. A comparison of several means of pyrometry, monochromatic, bi-chromatic and photothermal, is performed on an experiment of temperature measurement. We show that this measurement is sensitive to temperature gradients on the observed area. Layers resulting from carbon deposition by the plasma on the surface of components are modeled through a field of equivalent thermal resistance, without thermal inertia. The field of this resistance is determined, for each measurement points, from a comparison of surface temperature from infrared thermographs with the result of a simulation, which is based on a mono-dimensional linear model of components. The spatial distribution of the deposit on the component surface is obtained. Finally, a three-dimensional and non-linear computation of fields of heat fluxes, based on a finite element method, is developed here. Exact geometries of the component are used. The sensitivity of the computed heat fluxes is discussed regarding the accuracy of the temperature measurements. This computation is applied to two-dimensional temperature measurements of the JET tokamak. Several components of this tokamak are modeled, such as tiles of the divertor, upper limiter and inner and outer poloidal limiters. The distribution of heat fluxes on the surface of these components is computed and studied along the two main tokamak directions, poloidal and toroidal. Toroidal symmetry of the heat loads from one tile to another is shown. The influence of measurements spatial resolution

Rocket-borne thermal plasma instrument "MIPEX" for the ionosphere D, E layer in-situ measurements

Science.gov (United States)

Fang, H. K.; Chen, A. B. C.; Lin, C. C. H.; Wu, T. J.; Liu, K. S.; Chuang, C. W.

2017-12-01

In this presentation, the design concepts, performances and status of a thermal plasma particle instrument package "Mesosphere and Ionosphere Plasma Exploration complex (MIPEX)", which is going to be installed onboard a NSPO-funded hybrid rocket, to investigate the electrodynamic processes in ionosphere D, E layers above Taiwan are reported. MIPEX is capable of measuring plasma characteristics including ion temperature, ion composition, ion drift, electron temperature and plasma density at densities as low as 1-10 cm-1. This instrument package consists of an improved retarding potential analyzer with a channel electron multiplier (CEM), a simplified ion drift meter and a planar Langmuir probe. To achieve the working atmospheric pressure of CEM at the height of lower D layer ( 70km), a portable vacuum pump is also placed in the package. A prototype set of the MIPEX has been developed and tested in the Space Plasma Operation Chamber (SPOC) at NCKU, where in ionospheric plasma is generated by back-diffusion plasma sources. A plasma density of 10-106 cm-1, ion temperature of 300-1500 K and electron temperature of 1000-3000K is measured and verified. Limited by the flight platform and the performance of the instruments, the in-situ plasma measurements at the Mesosphere and lower Thermosphere is very challenging and rare. MIPEX is capable of extending the altitude of the effective plasma measurement down to 70 km height and this experiment can provide unique high-quality data of the plasma environment to explore the ion distribution and the electrodynamic processes in the Ionosphere D, E layers at dusk.

[Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

Science.gov (United States)

Li, Xue-chen; Yuan, Ning; Jia, Peng-ying; Niu, Dong-ying

2010-11-01

A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed. Furthermore, emission spectrum from the plasma plume was collected by high-resolution optical spectrometer. The emission spectra of OH (A 2sigma + --> X2 II, 307.7-308.9 nm) and the first negative band of N2+ (B2 sigma u+ --> X2 IIg+, 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The rotational temperature obtained is about 443 K by fitting the emission spectrum from the OH, and that from the first negative band of N2+ is about 450 K. The rotational temperatures obtained by the two method are consistent within 5% error band. The gas temperature of the plasma plume at atmospheric pressure was obtained because rotational temperature equals to gas temperature approximately in gas discharge at atmospheric pressure. Results show that gas temperature increases with increasing the applied voltage.

Industrial applications of low-temperature plasma physics

International Nuclear Information System (INIS)

Chen, F.F.

1995-01-01

The application of plasma physics to the manufacturing and processing of materials may be the new frontier of our discipline. Already partially ionized discharges are used in industry, and the performance of plasmas has a large commercial and technological impact. However, the science of low-temperature plasmas is not as well developed as that of high-temperature, collisionless plasmas. In this paper several major areas of application are described and examples of forefront problems in each are given. The underlying thesis is that gas discharges have evolved beyond a black art, and that intellectually challenging problems with elegant solutions can be found. copyright 1995 American Institute of Physics

Powder free PECVD epitaxial silicon by plasma pulsing or increasing the growth temperature

Science.gov (United States)

Chen, Wanghua; Maurice, Jean-Luc; Vanel, Jean-Charles; Cabarrocas, Pere Roca i.

2018-06-01

Crystalline silicon thin films are promising candidates for low cost and flexible photovoltaics. Among various synthesis techniques, epitaxial growth via low temperature plasma-enhanced chemical vapor deposition is an interesting choice because of two low temperature related benefits: low thermal budget and better doping profile control. However, increasing the growth rate is a tricky issue because the agglomeration of clusters required for epitaxy leads to powder formation in the plasma. In this work, we have measured precisely the time evolution of the self-bias voltage in silane/hydrogen plasmas at millisecond time scale, for different values of the direct-current bias voltage applied to the radio frequency (RF) electrode and growth temperatures. We demonstrate that the decisive factor to increase the epitaxial growth rate, i.e. the inhibition of the agglomeration of plasma-born clusters, can be obtained by decreasing the RF OFF time or increasing the growth temperature. The influence of these two parameters on the growth rate and epitaxial film quality is also presented.

Density and potential measurements in an intense ion-beam-generated plasma

International Nuclear Information System (INIS)

Abt, N.E.

1982-05-01

Neutral beams are created by intense large area ion beams which are neutralized in a gas cell. The interaction of the beam with the gas cell creates a plasma. Such a plasma is studied here. The basic plasma parameters, electron temperature, density, and plasma potential, are measured as a function of beam current and neutral gas pressure. These measurements are compared to a model based on the solution of Poisson's equation. Because of the cylindrical geometry the equation cannot be solved analytically. Details of the numerical method are presented

Arc generators of low-temperature plasma

International Nuclear Information System (INIS)

Krolikowski, Cz.; Niewiedzial, R.; Siwiec, J.

1979-01-01

This paper is a review of works concerning investigation and use of low-temperature plasma in arc plasma generators made in Electric Power Institute of PP. There are discussed: analytical approach to a problem of volt-current and operational characteristics of DC arc plasma generators, determination of limits of their stable work and possibilities of their use to technological aims. (author)

Measurement of Individual H+ and O+ Ion Temperatures in the Topside Ionosphere

Science.gov (United States)

Hsu, Chih-Te; Heelis, Roderick A.

2018-02-01

Plasma temperatures in the ionosphere are associated with both the dynamics and spatial distribution of the neutral and charge particles. During the daytime, temperatures are determined by solar energy inputs and energy exchange between charged and neutral particles. Plasma transport parallel to the magnetic field adds another influence on temperatures through adiabatic processes that are most evident during the nighttime. Previous observations suggest that the topside H+ temperature (TH+) should reside between the O+ temperature (TO+) and the electron temperature (Te), and further calculations confirm the preferential heat transfer from the electrons to H+ in the topside. In this work we implement a more sophisticated analysis procedure to extract individual mass-dependent ion temperatures from the retarding potential analyzer measurements on the DMSP F15 satellite. The results show that the daytime TH+ is a few hundred degrees higher than TO+ at all longitudes. The nighttime temperature difference between TH+ and TO+ is indicative of mass-dependent adiabatic heating and cooling processes across the equatorial region. The ion temperatures and measured plasma flows present clear longitudinal variations that are associated with magnetic declination.

Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

2007-05-15

In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

Effects of emitted electron temperature on the plasma sheath

International Nuclear Information System (INIS)

Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.

2014-01-01

It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03T e /e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux

Observation of electron plasma waves in plasma of two-temperature electrons

International Nuclear Information System (INIS)

Ikezawa, Shunjiro; Nakamura, Yoshiharu.

1981-01-01

Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

Determination of composition and physical properties of partially ionized plasmas in the function of temperature

International Nuclear Information System (INIS)

Zaporowski, B.

1992-01-01

The investigations of various kinds of partially ionized plasma were conducted for the pressure of 0.1 MPa and in the range of temperature of 298.15 K to 24000 K. The physical properties of various kinds of partially ionized plasma depend mainly of their composition and temperature. The composition of particular kinds of partially ionized plasmas varies also in the function of temperature. Simultaneous going on of physical and chemical processes in plasma is the reason of difficulties in the calculations of plasma's physical properties. The use of the laws of macroscopic thermodynamics for the calculations of physical properties of partially ionized plasma is impossible. There are enough exact methods for measuring of physical properties of partially ionized plasma. For these reasons the theoretical method using the base of statistic physics was used to calculate the composition and physical properties of various kinds of partially ionized plasma. (author) 2 refs., 2 figs

Equipment of Thomson scattering measurement on DIVA plasma

International Nuclear Information System (INIS)

Yamauchi, Toshihiko; Kumagai, Katsuaki; Funahashi, Akimasa; Matoba, Thoru; Sengoku, Seio

1980-02-01

Equipment of Thomson scattering measurement using ruby-laser light is explained. DIVA device was shut down in September 1979; it gave numerous fruitful experimental results during its five years operation. We measured the profiles of electron temperature and density with the Thomson scattering equipment, which played an important role in research of the energy confinement and heating characteristics. In Thomson scattering measurements on DIVA, studies and improvements were made for reduction of stray light, increase of measuring points and data processing. The profile of electron temperature and density were thus measured successful. In this report is given an over-all view of the Thomson scattering equipment together with the above improvements. As two representative examples, the measured results of electron temperature profiles on DIVA plasma under divertor operation and low-q discharge respectively are described. (author)

Asymmetric double Langmuir probe for fast and automatic measurements of plasma temperature

International Nuclear Information System (INIS)

Uckan, T.

1987-11-01

We present a fast technique for determining the plasma electron temperature T/sub e/ automatically from the small signal application of the asymmetric double Langmuir probe when it is operated in the region where -1 < eV/sub a/T/sub e/ < 1. The method described here is based on simple time and rms averages of the probe current that results from a sinusoidally varying applied voltage V/sub a/. 4 refs., 2 figs

Recombination in deuterium plasma at cryogenic temperatures (down to 130 K)

Energy Technology Data Exchange (ETDEWEB)

Novotny, O.; Glosik, J.; Pysanenko, A.; Zakouril, P.; Plasil, R.; Tichy, M. [Prague Charles Univ., Faculty of Mathematics and Physics (Czech Republic)

2004-07-01

The ions H{sub 3}{sup +} and D{sub 3}{sup +} play an important role in the kinetics of media of astrophysical interest but also in laboratory produced plasmas (discharges, fusion plasmas). In the presented study variable temperature flowing afterglow with Langmuir probe (VT-FALP) was used to study plasma decay in D{sub 2}/He mixture at temperatures down to 130 K and total pressure up to 10 Torr. Large extend of partial number densities of D{sub 2} (10{sup 12} - 3 x 10{sup 15} cm{sup -3}) were used in the experiments. Langmuir probes and mass spectrometers were applied to monitor decay of the plasma during the afterglow. The study is a continuation of our previous measurements of recombination rate coefficients of D{sub 3}{sup +} and D{sub 5}{sup +} ions. In these studies we observed dependence of the recombination rate coefficient on partial pressure of deuterium indicating that third-body assisted recombination is efficient and significantly contributes to recombination in decaying deuterium-containing plasma. (authors)

Measurements of Plasma Expansion due to Background Gas in the Electron Diffusion Gauge Experiment

International Nuclear Information System (INIS)

Morrison, Kyle A.; Paul, Stephen F.; Davidson, Ronald C.

2003-01-01

The expansion of pure electron plasmas due to collisions with background neutral gas atoms in the Electron Diffusion Gauge (EDG) experiment device is observed. Measurements of plasma expansion with the new, phosphor-screen density diagnostic suggest that the expansion rates measured previously were observed during the plasma's relaxation to quasi-thermal-equilibrium, making it even more remarkable that they scale classically with pressure. Measurements of the on-axis, parallel plasma temperature evolution support the conclusion

Investigation of the connection between plasma temperature and electrode temperature in metal-halide lamps

International Nuclear Information System (INIS)

Fromm, D.C.; Gleixner, K.H.; Lieder, G.H.

2002-01-01

Spatial profiles of electrode temperatures and plasma temperatures have been measured on 'real' HID lamps filled with a commercial metal-halide compound. The absolute accuracy of pyrometric determination of electrode tip temperatures was ±30 K, while the determination of plasma core temperatures, using a modified Bartels method, has an accuracy of ±100 K. We could deduce a close correlation between the plasma temperature in front of an electrode T p and its tip temperature T t due to the influence of the cataphoresis. If T p is reduced at the cathode the T t value has also lowered, whereas T p at the anode is raised together with its T t data. This correlation disappears at ballast frequencies above 100 Hz, whereas the cataphoresis influence on T p continues up to 500 Hz. Based on the latter limit, a rough estimation of the cataphoresis velocity delivers 700 cm s -1 . As a tentative interpretation, we suggest that the connection between T p and T t is caused by an increase of the ion part of the total current at the cathode due to Na accumulation before it. Thus, the cathode has to emit fewer electrons and works at a lower temperature. Further results are the temporal behaviour of T t depends on the ballast type. For vertical operation the strong influence of convection on T t has also to be taken into account. Above 100 Hz, where only convection plays a role, the upper electrode T t exceeds the T t value of the lower electrode by nearly 400 K. This discrepancy one may explain, tentatively, by convection heating of the upper electrode and convection cooling of the lower one. (author)

Spectroscopic measurements of anode plasma with cryogenic pulsed ion sources

International Nuclear Information System (INIS)

Yoneda, H.; Urata, T.; Ohbayashi, K.; Kim, Y.; Horioka, K.; Kasuya, K.

1987-01-01

In ion beam diodes, electromagnetic wave is coupled to ion beam. Ion is extracted from anode plasma, which is produced early in the power pulse. However, exact mechanism of anode plasma production, expansion and ion extraction process is unknown. In particularly, anode plasma expansion is seemed to be one of the reasons of rapid impedance collapse of the diode, which is serious problem in high power experiments. Some experimental results showed that anode plasma expansion velocity was about 5 times larger than that inferred from simple thermal velocity. Several explanations for these results were proposed; for example, electron collisionarity in anode plasma, fast neutral gas particle, diamagnetism. To solve this question, it is necessary to measure the characteristic of anode plasma with space and time resolution. The authors made spectroscopic measurements to investigate variety of electron temperature, electron density, expansion velocity of anode plasma with various ion sources

Motional Stark Effect measurements of the local magnetic field in high temperature fusion plasmas

Science.gov (United States)

Wolf, R. C.; Bock, A.; Ford, O. P.; Reimer, R.; Burckhart, A.; Dinklage, A.; Hobirk, J.; Howard, J.; Reich, M.; Stober, J.

2015-10-01

The utilization of the Motional Stark Effect (MSE) experienced by the neutral hydrogen or deuterium injected into magnetically confined high temperature plasmas is a well established technique to infer the internal magnetic field distribution of fusion experiments. In their rest frame, the neutral atoms experience a Lorentz electric field, EL = v × B, which results in a characteristic line splitting and polarized line emission. The different properties of the Stark multiplet allow inferring, both the magnetic field strength and the orientation of the magnetic field vector. Besides recording the full MSE spectrum, several types of polarimeters have been developed to measure the polarization direction of the Stark line emission. To test physics models of the magnetic field distribution and dynamics, the accuracy requirements are quite demanding. In view of these requirements, the capabilities and issues of the different techniques are discussed, including the influence of the Zeeman Effect and the sensitivity to radial electric fields. A newly developed Imaging MSE system, which has been tested on the ASDEX Upgrade tokamak, is presented. The sensitivity allows to resolve sawtooth oscillations. A shorter version of this contribution is due to be published in PoS at: 1st EPS conference on Plasma Diagnostics

Influence of the choice of internal temperatures on the composition of CxHyOzNt plasmas out of thermodynamic equilibrium: Application to CH2 plasma

International Nuclear Information System (INIS)

Koalaga, Zacharie

2002-01-01

The purpose of this paper is to study the influence of the choice of internal temperatures on the composition of C x H y O z N t plasmas out of thermodynamic equilibrium. The numerical calculation is specially performed for CH 2 plasma in the pressure range 0.1-1 MPa and for the electron temperature range 5000-30 000 K. Precisely, the investigation of this plasma allows one to show that the choice of internal temperatures can have more influence on plasma composition than the choice of the form of the two-temperature Saha and Guldberg-Waage laws. Indeed, for one of the supposed hypotheses, it is observed that the two forms of the two-temperature system used here can give the same equilibrium composition by uncoupling the excitation temperature of the diatomic and the monatomic species. Great attention must then be given to the adopted hypothesis for internal temperature and not only to the form of the two temperature system used. An accurate comparison between the two models requires the measurement of plasma parameters such as the various internal temperatures and the species concentration. Therefore, we have also carried out an analysis of the potential experimental diagnostics of these plasma parameters. Such diagnostics can help to test and validate theoretical models

CONFINEMENT OF HIGH TEMPERATURE PLASMA

Science.gov (United States)

Koenig, H.R.

1963-05-01

The confinement of a high temperature plasma in a stellarator in which the magnetic confinement has tended to shift the plasma from the center of the curved, U-shaped end loops is described. Magnetic means are provided for counteracting this tendency of the plasma to be shifted away from the center of the end loops, and in one embodiment this magnetic means is a longitudinally extending magnetic field such as is provided by two sets of parallel conductors bent to follow the U-shaped curvature of the end loops and energized oppositely on the inside and outside of this curvature. (AEC)

Generator of the low-temperature heterogeneous plasma flow

Science.gov (United States)

Yusupov, D. I.; Gadzhiev, M. Kh; Tyuftyaev, A. S.; Chinnov, V. F.; Sargsyan, M. A.

2018-01-01

A generator of low-temperature dc plasma with an expanding channel of an output electrode for gas-thermal spraying was designed and constructed. The delivery of the sprayed powder into the cathode and anode arc-binding zones or into the plasma jet below the anode binding was realized. The electrophysical characteristics of both the plasma torch and the heterogeneous plasma flow with Al2O3 powder are studied. It is shown that the current-voltage characteristic (CVC) of a plasma torch depends on the gas flow rate. If the flow rate varies from 1 to 3 g/s, the falling CVC becomes gradually increasing. The speed and temperature of the sprayed powder are determined.

Ion Flux Measurements in Electron Beam Produced Plasmas in Atomic and Molecular Gases

Science.gov (United States)

Walton, S. G.; Leonhardt, D.; Blackwell, D. D.; Murphy, D. P.; Fernsler, R. F.; Meger, R. A.

2001-10-01

In this presentation, mass- and time-resolved measurements of ion fluxes sampled from pulsed, electron beam-generated plasmas will be discussed. Previous works have shown that energetic electron beams are efficient at producing high-density plasmas (10^10-10^12 cm-3) with low electron temperatures (Te < 1.0 eV) over the volume of the beam. Outside the beam, the plasma density and electron temperature vary due, in part, to ion-neutral and electron-ion interactions. In molecular gases, electron-ion recombination plays a significant role while in atomic gases, ion-neutral interactions are important. These interactions also determine the temporal variations in the electron temperature and plasma density when the electron beam is pulsed. Temporally resolved ion flux and energy distributions at a grounded electrode surface located adjacent to pulsed plasmas in pure Ar, N_2, O_2, and their mixtures are discussed. Measurements are presented as a function of operating pressure, mixture ratio, and electron beam-electrode separation. The differences in the results for atomic and molecular gases will also be discussed and related to their respective gas-phase kinetics.

Electron temperature measurement in Z-pinch

International Nuclear Information System (INIS)

Gerusov, A.V.; Orlov, M.M.; Terent'ev, A.R.; Khrabrov, V.A.

1987-01-01

Measurement of temperature of emitting plasma sheath in noncylindrical Z-pinch in neon at the stage of convergence to the axis, based on comparing the intensity of spectral lines belonging to Ne1, Ne2, is performed. Line intensity relation dependence was determined using calculations according to emitting-collision model. Spectra were recorded by electron-optical converter and relative intensity was determined by subsequent photometry of photolayer. Cylindric symmetrical MHD-calculations during which temperature and the observed line intensity relation were determined, are conducted

Foundations of low-temperature plasma physics—an introduction

Science.gov (United States)

von Keudell, A.; Schulz-von der Gathen, V.

2017-11-01

The use of plasmas as a reactive mixture of ions, electrons and neutrals is at the core of numerous technologies in industry, enabling applications in microelectronics, automotives, packaging, environment and medicine. Recently, even the use of plasmas in medical applications has made great progress. The dominant character of a plasma is often its non equilibrium nature with different temperatures for the individual species in a plasma, the ions, electrons and neutrals. This opens up a multitude of reaction pathways which are inaccessible to conventional methods in chemistry, for example. The understanding of plasmas requires expertise in plasma physics, plasma chemistry and in electrical engineering. This first paper in a series of foundation papers on low temperature plasma science is intended to provide the very basics of plasmas as a common starting point for the more in-depth discussion of particular plasma generation methods, plasma modeling and diagnostics in the other foundation papers. In this first paper of the series, the common terminology, definitions and main concepts are introduced. The covered aspects start with the basic definitions and include further plasma equilibria, particle collisions and transport, sheaths and discharge breakdowns.

Simultaneous measurement of 3 fluctuating plasma parameters

International Nuclear Information System (INIS)

Carlson, A.; Giannone, L.

1991-01-01

Langmuir triple probes can provide simultaneous measurements of n e , T e and V pl with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (author) 1 fig

Simultaneous measurement of 3 fluctuating plasma parameters

International Nuclear Information System (INIS)

Carlson, A.; Giannone, L.

1991-01-01

Langmuir triple probes can provide simultaneous measurements of n e , T e , and V pl with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (orig.)

Simultaneous measurement of 3 fluctuating plasma parameters

Energy Technology Data Exchange (ETDEWEB)

Carlson, A; Giannone, L. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany))

1991-01-01

Langmuir triple probes can provide simultaneous measurements of n[sub e], T[sub e] and V[sub pl] with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (author) 1 fig.

Effects of lower hybrid fast electron populations on electron temperature measurements at JET

International Nuclear Information System (INIS)

Tanzi, C.P.; Bartlett, D.V.; Schunke, B.

1993-01-01

The Lower Hybrid Current Drive (LHCD) system on JET has to date achieved up to 1.5 MA of driven current. This current is carried by a fast electron population with energies more than ten times the electron temperature and density about 10 -4 of the bulk plasma. This paper discusses the effects of this fast electron population on our ability to make reliable temperature measurements using ECE and reviews the effects on other plasma diagnostics which rely on ECE temperature measurements for their interpretation. (orig.)

Plasma flow measurements in the Prototype-Material Plasma Exposure eXperiment (Proto-MPEX) and comparison with B2.5-Eirene modeling

Science.gov (United States)

Kafle, N.; Owen, L. W.; Caneses, J. F.; Biewer, T. M.; Caughman, J. B. O.; Donovan, D. C.; Goulding, R. H.; Rapp, J.

2018-05-01

The Prototype Material Plasma Exposure eXperiment (Proto-MPEX) at Oak Ridge National Laboratory is a linear plasma device that combines a helicon plasma source with additional microwave and radio frequency heating to deliver high plasma heat and particle fluxes to a target. Double Langmuir probes and Thomson scattering are being used to measure local electron temperature and density at various radial and axial locations. A recently constructed Mach-double probe provides the added capability of simultaneously measuring electron temperatures ( T e), electron densities ( n e), and Mach numbers (M). With this diagnostic, it is possible to infer the plasma flow, particle flux, and heat flux at different locations along the plasma column in Proto-MPEX. Preliminary results show Mach numbers of 0.5 (towards the dump plate) and 1.0 (towards the target plate) downstream from the helicon source, and a stagnation point (no flow) near the source for the case where the peak magnetic field was 1.3 T. Measurements of particle flow and ne and Te profiles are discussed. The extensive coverage provided by these diagnostics permits data-constrained B2.5-Eirene modeling of the entire plasma column, and comparison with results of modeling in the high-density helicon plasmas will be presented.

Measurement of air entrainment in plasma jets

International Nuclear Information System (INIS)

Fincke, J.R.; Rodriquez, R.; Pentecost, C.G.

1990-01-01

The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing. 9 refs., 5 figs., 1 tab

Direct measurement of the plasma response to electrostatic ion waves

International Nuclear Information System (INIS)

Sarfaty, M.; DeSouza-Machado, S.; Skiff, F.

1995-01-01

Plasma wave-wave and wave-particle interactions are studied in a linear magnetized plasma. The relatively quiet plasma is produced by an argon gas-discharge. The plasma density is n e ≅ 10 9 cm -3 and the electron/ion temperatures are T e ≅ 5eV and T i = 0.05eV. A grid and a four ring antenna, both mounted on a scanning carriage, are used to launch electrostatic ion waves in the plasma. Laser Induced Fluorescence measurements of both the linear and the nonlinear plasma response to the wave fields are presented. The Vlasov-Poisson equations are used to explain the measured zero, first and second order terms of the ion distribution function in the presence of wave fields. In addition to the broadening (heating) of the ion distribution as the authors increase the wave amplitudes, induced plasma flows are observed both along and across the magnetic field

A small spacecraft for multipoint measurement of ionospheric plasma

Science.gov (United States)

Roberts, T. M.; Lynch, K. A.; Clayton, R. E.; Weiss, J.; Hampton, D. L.

2017-07-01

Measurement of ionospheric plasma is often performed by a single in situ device or remotely using cameras and radar. This article describes a small, low-resource, deployed spacecraft used as part of a local, multipoint measurement network. A B-field aligned sounding rocket ejects four of these spin-stabilized spacecraft in a cross pattern. In this application, each spacecraft carries two retarding potential analyzers which are used to determine plasma density, flow, and ion temperature. An inertial measurement unit and a light-emitting diode array are used to determine the position and orientation of the devices after deployment. The design of this spacecraft is first described, and then results from a recent test flight are discussed. This flight demonstrated the successful operation of the deployment mechanism and telemetry systems, provided some preliminary plasma measurements in a simple mid-latitude environment, and revealed several design issues.

Frugal Biotech Applications of Low-Temperature Plasma.

Science.gov (United States)

Machala, Zdenko; Graves, David B

2017-09-01

Gas discharge low-temperature air plasma can be utilized for a variety of applications, including biomedical, at low cost. We term these applications 'frugal plasma' - an example of frugal innovation. We demonstrate how simple, robust, low-cost frugal plasma devices can be used to safely disinfect instruments, surfaces, and water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measurement of the central ion and electron temperature of tokamak plasmas from the x-ray line radiation of high-Z impurity ions

International Nuclear Information System (INIS)

Bitter, M.; von Goeler, S.; Goldman, M.; Hill, K.W.; Horton, R.; Roney, W.; Sauthoff, N.; Stodiek, W.

1982-04-01

This paper describes measurements of the central ion and electron temperature of tokamak plasmas from the observation of the 1s - 2p resonance lines, and the associated dielectronic (1s 2 nl - 1s2pnl, with n greater than or equal to 2) satellites, of helium-like iron (Fe XXV) and titanium (Ti XXI). The satellite to resonance line ratios are very sensitive to the electron temperature and are used as an electron temperature diagnostic. The ion temperature is deduced from the Doppler width of the 1s - 2p resonance lines. The measurements have been performed with high resolution Bragg crystal spectrometers on the PLT (Princeton Large Torus) and PDX (Poloidal Divertor Experiment) tokamaks. The details of the experimental arrangement and line evaluation are described, and the ion and electron temperature results are compared with those obtained from independent diagnostic techniques, such as the analysis of charge-exchange neutrals and measurements of the electron cyclotron radiation. The obtained experimental results permit a detailed comparison with theoretical predictions

Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

International Nuclear Information System (INIS)

Čeřovský, M.; Khun, J.; Rusová, K.; Scholtz, V.; Soušková, H.

2013-01-01

The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials

Inactivation of possible micromycete food contaminants using the low-temperature plasma and hydrogen peroxide

Energy Technology Data Exchange (ETDEWEB)

Čeřovský, M., E-mail: scholtz@aldebaran.cz [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic); Khun, J. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Rusová, K. [Institute of Chemical Technology in Prague, Department of Food Preservation, Faculty of Food and Biochemical Technology (Czech Republic); Scholtz, V. [Institute of Chemical Technology in Prague, Department of Physics and Measurements, Faculty of Chemical Engineering (Czech Republic); Soušková, H. [Institute of Chemical Technology in Prague, Department of Computing and Control Engineering, Faculty of Chemical Engineering (Czech Republic)

2013-09-15

The inhibition effect of hydrogen peroxide aerosol, low-temperature plasma and their combinations has been studied on several micromycetes spores. The low-temperature plasma was generated in corona discharges in the open air apparatus with hydrogen peroxide aerosol. Micromycete spores were inoculated on the surface of agar plates, exposed solely to the hydrogen peroxide aerosol, corona discharge or their combination. After incubation the diameter of inhibition zone was measured. The solely positive corona discharge exhibits no inactivation effect, the solely negative corona discharge and solely hydrogen peroxide aerosol exhibit the inactivation effect, however their combinations exhibit to be much more effective. Low-temperature plasma and hydrogen peroxide aerosol present a possible alternative method of microbial decontamination of food, food packages or other thermolabile materials.

Analysis of electron cyclotron emission spectra of high electron temperature, supershot plasmas in TFTR

International Nuclear Information System (INIS)

Taylor, G.; Arunasalam, V.; Efthimion, P.C.; Grek, B.

1993-01-01

A primary objective of the TFTR program since 1986 has been the study and optimization of deuterium Supershot plasmas. These plasmas are predominantly heated by 90-110 keV neutral deuterium beams (P NBI /P OH >30), central ion temperatures are ∝30 keV and central electron temperatures from ECE (T ECE ) often exceed 10 keV. Central electron temperature data measured with a TV Thomson scattering (TVTS) system (T TVTS ) during the period 1987-1990 have been compared with data from three different ECE instruments on TFTR. Although T ECE ∝T TVTS for temperatures below 6 keV, there is a systematically increasing disagreement at higher electron temperatures, with T ECE ∝1.2 T TVTS for T TVTS in the range 9-10 keV. Recent theoretical work on the ECE radiation temperature of non-equilibrium plasmas indicates that for a bi-Maxwellian electron velocity distribution with a ratio of tail to bulk electron density η, a bulk temperature T b , and a hot tail temperature T h , the perpendicular ECE radiation temperature is given by T ECE ∝T b {1+η(T h /T b )}, for η ECE would be enhanced over T TVTS by a factor which depends on η and T h . This paper investigates whether the discrepancy between T TVTS and T ECE seen in TFTR Supershots at high electron temperatures is due to the presence of a hot electron tail component. The extraordinary mode ECE spectrum at the second, third and fourth harmonics is measured on the horizontal midplane by an absolutely calibrated ECE Michelson interferometer. This ECE spectrum is compared with the output from a time-independent transport code with relativistic opacity which solves the three-dimensional ECE radiation transport in a toroidally symmetric, two-dimensional geometry and uses measured electron density and temperature profiles from the TVTS system. (orig.)

Magnetic Field Measurements In Magnetized Plasmas Using Zeeman Broadening Diagnostics

Science.gov (United States)

Haque, Showera; Wallace, Matthew; Presura, Radu; Neill, Paul

2017-10-01

The Zeeman effect has been used to measure the magnetic field in high energy density plasmas. This method is limited when plasma conditions are such that the line broadening due to the high plasma density and temperature surpasses the Zeeman splitting. We have measured magnetic fields in magnetized laser plasmas under conditions where the Zeeman splitting was not spectrally resolved. The magnetic field strength was determined from the difference in widths of two doublet components, using an idea proposed by Tessarin et al. (2011). Time-gated spectra with one-dimensional space-resolution were obtained at the Nevada Terawatt Facility for laser plasmas created by 20 J, 1 ns Leopard laser pulses, and expanding in the azimuthal magnetic field produced by the 0.6 MA Zebra pulsed power generator. We explore the response of the Al III 4s 2S1/2 - 4p 2P1 / 2 , 3 / 2 doublet components to the external magnetic field spatially along the plasma. Radial magnetic field and electron density profiles were measured within the plasma plume. This work was supported by the DOE/OFES Grant DE-SC0008829 and DOE/NNSA contract DE-FC52-06NA27616.

The physics of the low-temperature plasma in Czechoslovakia

International Nuclear Information System (INIS)

Kracik, J.

1985-01-01

A survey is given of low-temperature plasma research in Czechoslovakia since 1954 and its main results are pointed out. In the first years, various processes in electric discharges and electromagnetic acceleration of plasma clusters were studied at Czechoslovak universities and in the Institute of Physics. In the study of ionization waves, Czechoslovak physicists achieved world priority. Later on, low-temperature plasma investigation began in the Institute of Plasma Physics, founded in 1959. The issues of plasma interaction with the solid state and plasma applications in plasma chemistry were studied mainly by its Department of Applied Plasma Physics. The main effort of this group, transferred recently to the Institute of Physics, is aimed at thin film production and plasma-surface interactions; similar experimental studies are also carried out at universities in Brno and Bratislava. Last but not least, arc spraying of powder materials using water-cooled plasmatrons is being developed by the Department of Plasma Technology of the Institute of Plasma Physics. (J.U.)

Neutron localization measurements from a two-gun plasma focus device

International Nuclear Information System (INIS)

Yeh, T.R.; Wen, M.; Tzeng, C.C.; Shang, D.J.; Yeh, C.K.; Wu, K.S.; Kuo, Y.Y.; Hou, W.S.

1989-01-01

The simultaneous formation of the two deuterium plasma foci has been reported recently by Hou, W.S., et al, in Procs I.E.E.E. Int. Conf. on Plasma Science, 1986, 87, in a Mather type two-gun plasma focus assembly with maximum bank energy of ∼700 kJ. In addition, these plasmas will evolve and then produce a disk-shaped plasma in the middle of the two plasma foci. Soft X-ray filter techniques which allow measurements of the electron temperature at both pinch points and the middle point yielded a few hundred eV for these three regions. Neutron localization measurements which were carried out with a collimator and a scintillator-fiber-photomultiplier assembly indicate that an enhancement of ∼80% in neutron yield is observed in the middle region as the separation between two electrodes is 9.1 cm. Further experimental evidence shows that the neutron production in the middle region is the result of the beam-beam interaction in nature. (author)

Plasma gradient effects on double-probe measurements in the magnetosphere

Directory of Open Access Journals (Sweden)

H. Laakso

1995-02-01

Full Text Available The effects on double-probe electric field measurements induced by electron density and temperature gradients are investigated. We show that on some occasions such gradients may lead to marked spurious electric fields if the probes are assumed to lie at the same probe potential with respect to the plasma. The use of a proper bias current will decrease the magnitude of such an error. When the probes are near the plasma potential, the magnitude of these error signals, ∆E, can vary as ∆E ~ Te(∆ne/ne+0.5∆Te, where Te is the electron temperature, ∆ne/ne the relative electron density variation between the two sensors, and ∆Te the electron temperature difference between the two sensors. This not only implies that the error signals will increase linearly with the density variations but also that such signatures grow with Te, i.e., such effects are 10 times larger in a 10-eV plasma than in a 1-eV plasma. This type of error is independent of the probe separation distance provided the gradient scale length is much larger than this distance. The largest errors occur when the probes are near to the plasma potential. At larger positive probe potentials with respect to the plasma potential, the error becomes smaller if the probes are biased, as is usually the case with spherical double-probe experiments in the tenuous magnetospheric plasmas. The crossing of a plasma boundary (like the plasmapause or magnetopause yields an error signal of a single peak. During the crossing of a small structure (e.g., a double layer the error signal appears as a bipolar signature. Our analysis shows that errors in double-probe measurements caused by plasma gradients are not significant at large scale (»1 km plasma boundaries, and may only be important in cases where small-scale (<1 km, internal gradient structures exist. Bias currents tailored for each plasma parameter regime (i.e., variable bias current would o1q1improve the double-probe response to gradient

Thermal and nonthermal electron cyclotron emission by high-temperature tokamak plasmas

International Nuclear Information System (INIS)

Airoldi, A.; Ramponi, G.

1997-01-01

An analysis of the electron cyclotron emission (ECE) spectra emitted by a high-temperature tokamak plasma in the frequency range of the second and third harmonic of the electron cyclotron frequency is made, both in purely Maxwellian and in non-Maxwellian cases (i.e., in the presence of a current-carrying superthermal tail). The work is motivated mainly by the experimental observations made in the supershot plasmas of the Tokamak Fusion Test Reactor (TFTR), where a systematic disagreement is found between the T e measurements by second-harmonic ECE and Thomson scattering. We show that, by properly taking into account the overlap of superthermals-emitted third harmonic with second-harmonic bulk emission, the radiation temperature observed about the central frequency of the second harmonic may be enhanced up to 30%endash 40% compared to the corresponding thermal value. Moreover we show that, for parameters relevant to the International Thermonuclear Experimental Reactor (ITER) with T e (0)>7 keV, the overlap between the second and the downshifted third harmonic seriously affects the central plasma region, so that the X-mode emission at the second harmonic becomes unsuitable for local T e measurements. copyright 1997 American Institute of Physics

Plasma dynamics near critical density inferred from direct measurements of laser hole boring

Science.gov (United States)

Gong, Chao; Tochitsky, Sergei Ya.; Fiuza, Frederico; Pigeon, Jeremy J.; Joshi, Chan

2016-06-01

We have used multiframe picosecond optical interferometry to make direct measurements of the hole boring velocity, vHB, of the density cavity pushed forward by a train of C O2 laser pulses in a near critical density helium plasma. As the pulse train intensity rises, the increasing radiation pressure of each pulse pushes the density cavity forward and the plasma electrons are strongly heated. After the peak laser intensity, the plasma pressure exerted by the heated electrons strongly impedes the hole boring process and the vHB falls rapidly as the laser pulse intensity falls at the back of the laser pulse train. A heuristic theory is presented that allows the estimation of the plasma electron temperature from the measurements of the hole boring velocity. The measured values of vHB, and the estimated values of the heated electron temperature as a function of laser intensity are in reasonable agreement with those obtained from two-dimensional numerical simulations.

Measurement of the local particle diffusion coefficient in a magnetized plasma

International Nuclear Information System (INIS)

Meyerhofer, D.D.; Levinton, F.M.

1987-02-01

Local impurity particle diffusion coefficients have been measured in a low temperature plasma by the injection of test particles at the center of the plasma. The injection is accomplished by a high voltage discharge between two small graphite electrodes on a probe. The probe can be located anywhere in the plasma. The diffusion is observed spectroscopically. An analysis of the spatial and temporal evolution of the CII radiation from the carbon discharge can determine the parallel and perpendicular diffusion of the impurity ions. Results with the diagnostic have been obtained in the Proto S-1/C spheromak. The measured value of the diffusion coefficient in the afterglow plasma is in good agreement with classical predictions

Dense high-temperature plasma transport processes

International Nuclear Information System (INIS)

Giniyatova, Sh.G.

2002-01-01

In this work the transport processes in dense high-temperature semiclassical plasma are studied on the base of the kinetic equation, where the semiclassical potential was used, in its collision integral. The coefficient of plasma electrical conductivity, viscosity and thermal conductivity were received. There were compared with the other authors' results. The Grad's method was used obtaining of viscosity and thermal coefficients. (author)

Industrial Applications of Low Temperature Plasmas

International Nuclear Information System (INIS)

Bardsley, J N

2001-01-01

The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed

Enthalpy probe measurements and three-dimensional modelling on air plasma jets generated by a non-transferred plasma torch with hollow electrodes

International Nuclear Information System (INIS)

Kim, Keun Su; Park, Jin Myung; Choi, Sooseok; Kim, Jongin; Hong, Sang Hee

2008-01-01

Thermal flow characteristics of air plasma jets generated by a non-transferred plasma torch with hollow electrodes are experimentally and numerically investigated in order to provide more reliable scientific and technical information, which has been insufficient for their practical applications to material and environmental industries. In this work, a thermal plasma torch of hollow electrode type is first designed and fabricated, and similarity criteria for predicting operational conditions for the scale-up to high-power torches are derived from the arc voltage characteristics measured with various operating and geometry conditions of the torch. The thermal flow characteristics of air plasma jets ejected from the torch are measured by enthalpy probe diagnostics and turn out to have relatively low temperatures of around 3000-7000 K, but show features of other unique properties, such as high energy flux, broad high temperature region and long plasma jet with moderate axial velocity, which are promising for their applications to material syntheses and hazardous waste treatments. Such high enthalpy at a relatively low temperature of air thermal plasma compared with the argon one is due to the high thermal energy residing in the vibrational and rotational states and oxygen dissociation, besides the translational states in monatomic gases such as argon. It is expected that this high specific enthalpy of the air plasma will enable material and environmental industries to treat a large amount of precursors and waste materials effectively at a lower temperature for a longer residence time by the low plasma velocity. It is also found from the measurements that the turbulence intensity influenced by the size of the electrode diameter has a significant effect on the axial and radial profiles of plasma jet properties and that a longer plasma jet is more readily achievable with a larger electrode diameter reducing the turbulence intensity in the external region of the torch. In

Measurement of peripheral plasma using double probe in TRIAM-IM

International Nuclear Information System (INIS)

Yamagami, Masahiro; Kawasaki; Shoji; Jyotaki, Eriko; Fujita, Takaaki; Sakamoto, Mizuki; Nakamura, Kazuo; Nakamura, Yukio; Ito, Satoshi

1994-01-01

Behind the poloidal limiter of the TRIAM-IM, the change with time lapse of the electron temperature and the plasma density at the time of OH discharge was examined by using a double probe. Scrape-off plasma parameters, namely the correlations of electron temperature, plasma density and ion flux with main plasma parameters were obtained. It was found that scrape-off density is almost proportional to square of beam average electron density. Further, it was determined by calculation that the density on the outermost shell magnetic surface is about 1.5 x 10 15 /m 2 . In the TRIAM-IM, it is expected that accompanying the increase of plasma current at the time of OH discharge, the effects of thermal load and particle load given to the limiter and the first wall increase, and the increase of the metallic impurities due to sputtering becomes a serious problem. The merits of double probe method are explained. The objective of this experiment is to examine the temperature and density of the plasma that comes in contact with the limiter and the wall by determining the basic parameters of peripheral plasma at the time of OH discharge. In order to heighten the reliability of data, the examination was carried out from both aspects of hardware and software. The TRIAM-IM, double probe measuring system and its theory, applied voltage sweeping part, signal processing system, data processing system, and the experimental results of scrape-off layer parameters are described. (K.I.)

Design and first plasma measurements of the ITER-ECE prototype radiometer

Energy Technology Data Exchange (ETDEWEB)

Austin, M. E.; Brookman, M. W.; Rowan, W. L. [Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States); Danani, S. [ITER-India/Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); Bryerton, E. W.; Dougherty, P. [Virginia Diodes, Inc., Charlottesville, Virginia 22902 (United States)

2016-11-15

On ITER, second harmonic optically thick electron cyclotron emission (ECE) in the range of 220-340 GHz will supply the electron temperature (T{sub e}). To investigate the requirements and capabilities prescribed for the ITER system, a prototype radiometer covering this frequency range has been developed by Virginia Diodes, Inc. The first plasma measurements with this instrument have been carried out on the DIII-D tokamak, with lab bench tests and measurements of third through fifth harmonic ECE from high T{sub e} plasmas. At DIII-D the instrument shares the transmission line of the Michelson interferometer and can simultaneously acquire data. Comparison of the ECE radiation temperature from the absolutely calibrated Michelson and the prototype receiver shows that the ITER radiometer provides accurate measurements of the millimeter radiation across the instrument band.

Monitoring Temperature in High Enthalpy Arc-heated Plasma Flows using Tunable Diode Laser Absorption Spectroscopy

Science.gov (United States)

Martin, Marcel Nations; Chang, Leyen S.; Jeffries, Jay B.; Hanson, Ronald K.; Nawaz, Anuscheh; Taunk, Jaswinder S.; Driver, David M.; Raiche, George

2013-01-01

A tunable diode laser sensor was designed for in situ monitoring of temperature in the arc heater of the NASA Ames IHF arcjet facility (60 MW). An external cavity diode laser was used to generate light at 777.2 nm and laser absorption used to monitor the population of electronically excited oxygen atoms in an air plasma flow. Under the assumption of thermochemical equilibrium, time-resolved temperature measurements were obtained on four lines-of-sight, which enabled evaluation of the temperature uniformity in the plasma column for different arcjet operating conditions.

MOSS spectroscopic camera for imaging time resolved plasma species temperature and flow speed

International Nuclear Information System (INIS)

Michael, Clive; Howard, John

2000-01-01

A MOSS (Modulated Optical Solid-State) spectroscopic camera has been devised to monitor the spatial and temporal variations of temperatures and flow speeds of plasma ion species, the Doppler broadening measurement being made of spectroscopic lines specified. As opposed to a single channel MOSS spectrometer, the camera images light from plasma onto an array of light detectors, being mentioned 2D imaging of plasma ion temperatures and flow speeds. In addition, compared to a conventional grating spectrometer, the MOSS camera shows an excellent light collecting performance which leads to the improvement of signal to noise ratio and of time resolution. The present paper first describes basic items of MOSS spectroscopy, then follows MOSS camera with an emphasis on the optical system of 2D imaging. (author)

MOSS spectroscopic camera for imaging time resolved plasma species temperature and flow speed

Energy Technology Data Exchange (ETDEWEB)

Michael, Clive; Howard, John [Australian National Univ., Plasma Research Laboratory, Canberra (Australia)

2000-03-01

A MOSS (Modulated Optical Solid-State) spectroscopic camera has been devised to monitor the spatial and temporal variations of temperatures and flow speeds of plasma ion species, the Doppler broadening measurement being made of spectroscopic lines specified. As opposed to a single channel MOSS spectrometer, the camera images light from plasma onto an array of light detectors, being mentioned 2D imaging of plasma ion temperatures and flow speeds. In addition, compared to a conventional grating spectrometer, the MOSS camera shows an excellent light collecting performance which leads to the improvement of signal to noise ratio and of time resolution. The present paper first describes basic items of MOSS spectroscopy, then follows MOSS camera with an emphasis on the optical system of 2D imaging. (author)

Generation of low-temperature air plasma for food processing

Science.gov (United States)

Stepanova, Olga; Demidova, Maria; Astafiev, Alexander; Pinchuk, Mikhail; Balkir, Pinar; Turantas, Fulya

2015-11-01

The project is aimed at developing a physical and technical foundation of generating plasma with low gas temperature at atmospheric pressure for food industry needs. As known, plasma has an antimicrobial effect on the numerous types of microorganisms, including those that cause food spoilage. In this work an original experimental setup has been developed for the treatment of different foods. It is based on initiating corona or dielectric-barrier discharge in a chamber filled with ambient air in combination with a certain helium admixture. The experimental setup provides various conditions of discharge generation (including discharge gap geometry, supply voltage, velocity of gas flow, content of helium admixture in air and working pressure) and allows for the measurement of the electrical discharge parameters. Some recommendations on choosing optimal conditions of discharge generation for experiments on plasma food processing are developed.

The concept of temperature in space plasmas

Science.gov (United States)

Livadiotis, G.

2017-12-01

Independently of the initial distribution function, once the system is thermalized, its particles are stabilized into a specific distribution function parametrized by a temperature. Classical particle systems in thermal equilibrium have their phase-space distribution stabilized into a Maxwell-Boltzmann function. In contrast, space plasmas are particle systems frequently described by stationary states out of thermal equilibrium, namely, their distribution is stabilized into a function that is typically described by kappa distributions. The temperature is well-defined for systems at thermal equilibrium or stationary states described by kappa distributions. This is based on the equivalence of the two fundamental definitions of temperature, that is (i) the kinetic definition of Maxwell (1866) and (ii) the thermodynamic definition of Clausius (1862). This equivalence holds either for Maxwellians or kappa distributions, leading also to the equipartition theorem. The temperature and kappa index (together with density) are globally independent parameters characterizing the kappa distribution. While there is no equation of state or any universal relation connecting these parameters, various local relations may exist along the streamlines of space plasmas. Observations revealed several types of such local relations among plasma thermal parameters.

2. Basis of measurement of plasma flow. 2.3 Plasma flow measurements. Spectroscopic methods

International Nuclear Information System (INIS)

Kado, Shinichiro

2007-01-01

The construction of optical system, optical fiber incident system, reciprocal linear dispersion, grating smile and astigmatism of the reflection plane diffraction grating spectrometer are explained in order to measure the plasma flow. The specification of flow measurement and evaluation of 0 point of velocity are stated. For examples of measurements, the fine structures of He II (Δn = 3 - 4) in material and plasma(MAP)-II of Tokyo University, plasma flow measurement by the charge exchange recombination spectroscopy using Large Helical Device and by Zeeman spectroscopy using TRIAM-1M tokamak plasma are stated. (S.Y.)

Internal modes in high-temperature plasmas

International Nuclear Information System (INIS)

Crew, G.B.

1983-02-01

The linear stability of current-carrying toroidal plamsas is examined to determine the possibility of exciting global internal modes. The ideal magnetohydrodynamic (MHD) theory provides a useful framework for the analysis of these modes, which involve a kinking of the central portion of the plasma column. Non-ideal effects can also be important, and these are treated for high-temperature regimes where the plasma is collisionless

Influence of sample temperature on the expansion dynamics and the optical emission of laser-induced plasma

Energy Technology Data Exchange (ETDEWEB)

Eschlböck-Fuchs, S.; Haslinger, M.J.; Hinterreiter, A.; Kolmhofer, P.; Huber, N. [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Rössler, R. [voestalpine Stahl GmbH, A-4031 Linz (Austria); Heitz, J. [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria); Pedarnig, J.D., E-mail: johannes.pedarnig@jku.at [Christian Doppler Laboratory for Laser-Assisted Diagnostics, Institute of Applied Physics, Johannes Kepler University Linz, A-4040 Linz (Austria)

2013-09-01

We investigate the influence of sample temperature on the dynamics and optical emission of laser induced plasma for various solid materials. Bulk aluminum alloy, silicon wafer, and metallurgical slag samples are heated to temperature T{sub S} ≤ 500 °C and ablated in air by Nd:YAG laser pulses (wavelength 1064 nm, pulse duration approx. 7 ns). The plasma dynamics is investigated by fast time-resolved photography. For laser-induced breakdown spectroscopy (LIBS) the optical emission of plasma is measured by Echelle spectrometers in combination with intensified CCD cameras. For all sample materials the temporal evolution of plume size and broadband plasma emission vary systematically with T{sub S}. The size and brightness of expanding plumes increase at higher T{sub S} while the mean intensity remains independent of temperature. The intensity of emission lines increases with temperature for all samples. Plasma temperature and electron number density do not vary with T{sub S}. We apply the calibration-free LIBS method to determine the concentration of major oxides in slag and find good agreement to reference data up to T{sub S} = 450 °C. The LIBS analysis of multi-component materials at high temperature is of interest for technical applications, e.g. in industrial production processes. - Highlights: • Size and emission of laser-induced plasma increase with sample temperature Ts. • Mean optical intensity of plasma is independent of Ts. • Plasma temperature and electron number density do not vary with Ts. • Major oxides in steel slag are quantified up to Ts = 450 °C. • Industrial steel slags are analyzed by calibration-free LIBS method.

Confinement properties of JET plasmas with different temperature and density profiles

International Nuclear Information System (INIS)

Watkins, M.L.; Balet, B.; Bhatnagar, V.P.

1989-01-01

The confinement properties of plasmas with substantially different temperature and density profiles have been analysed. The effects of fast particles and energy pedestals on the overall confinement of plasma energy in limiter (L-mode) and X-point (L- and H-modes) discharges heated by NBI or ICRF or both are determined. The importance of the bootstrap current when such energy pedestals are formed is noted. Using sets of consistent experimental data, including ion temperature profile measurements, the local transport properties are compared in the L- and H-phases of a single null X-point medium density NBI heated discharge, the ''enhanced'' confinement phase of a limiter high density pellet-fuelled and ICRF heated discharge, the hot-ion phase of a double null X-point low density NBI heated discharge and the hot-ion and H-phases of a double null X-point low density high temperature NBI heated discharge. (author)

Experimental observations of the plasma properties of a high-density, low-temperature accelerated arc

International Nuclear Information System (INIS)

Thomas, K.A.

1991-01-01

The existence of an absorbing layer, or buffer zone, of weakly ionized gas between the rear of the projectile and the front of the plasma arc armature in a plasma accelerator was demonstrated. A technique was developed to accurately determine the position of the projectile as it accelerates along the bore of the device. The projectile position is compared to that of the plasma arc as measured by magnetic field probes. These measurements provide the basis for a description of the in-bore motion of the projectile with respect to the plasma arc. Observations of this motion in plasma accelerators of 0.6 and 2.4 m lengths show the buffer zone can be as large as 50 times the bore diameter. In-bore measurements of the broadband light emission and pressure of both the buffer region and the plasma arc armature are correlated with the known projectile position to determine the characteristics of both the buffer zone and the plasma arc. Time-integrated spectral measurements of the emission taken through both the side insulators and the electrodes indicate the existence of a nonuniform plasma temperature and of turbulence in the plasma. The presence of molecular species is attributed with the ablation of the side insulator material

Electron temperature and density profiles measurement in the TJ-1 tokamak by Thomson scattering

International Nuclear Information System (INIS)

Pardo, C.; Zurro, B.

1986-01-01

Electron temperature and density profiles of ohmically heated hydrogen plasmas in the TJ-1 tokamak have been measured by Thomson scattering. The temperature profile peaks sharply in the central region while the density profile is very flat. Temperature values between 100 and 390 eV have been measured for densities in the range of 5.10 12 to 2.6.10 13 cm -3 . Parameters characterizing TJ-1 plasma, such as confinement times Z eff , have been deduced from experimental data. Energy confinement times are compared with experimental scaling laws. (author)

2D simulations of hohlraum targets for laser-plasma experiments and ion stopping measurement in hot plasmas

Energy Technology Data Exchange (ETDEWEB)

Basko, M.M. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany). ExtreMe Matter Institute EMMI; Maruhn, J.; Tauschwitz, Anna [Frankfurt Univ. (Germany); Novikov, V.G.; Grushin, A.S. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

2011-12-15

An attractive way to create uniform plasma states at high temperatures and densities is by using hohlraums - cavities with heavy-metal walls that are either directly or indirectly heated by intense laser pulses to x-ray temperatures of tens and hundreds electron volts. A sample material, whose plasma state is to be studied, can be placed inside such a hohlraum (usually in the form of a low-density foam) and uniformly heated to a high temperature. In this case a high-Z hohlraum enclosure serves a double purpose: it prevents the hot plasma from rapid disassembly due to hydrodynamic expansion and, at the same time, suppresses its rapid radiative cooling by providing high diffusive resistivity for X-rays. Of course, both the inertial and the thermal confinement of high-temperature plasmas can be achieved only for a limited period of time - on the order of nanoseconds for millimeter-scale hohlraums. Some time ago such hohlraum targets were proposed for measurements of the stopping power of hot dense plasmas for fast ions at GSI (Darmstadt). Theoretical modeling of hohlraum targets has always been a challenging task for computational physics because it should combine multidimensional hydrodynamic simulations with the solution of the spectral transfer equation for thermal radiation. In this work we report on our latest progress in this direction, namely, we present the results of 2D (two-dimensional) simulations with a newly developed radiation-hydrodynamics code RALEF-2D of two types of the hohlraum targets proposed for experiments on the PHELIX laser at GSI. The first configuration is a simple spherical hohlraum with gold walls and empty interior, which has two holes - one for laser beam entrance, and the other for diagnostics. The hohlraums of this type have already been used in several experimental sessions with the NHELIX and PHELIX lasers at GSI. The second type is a two-chamber cylindrical hohlraum with a characteristic {omega}-shaped cross-section of the enclosure

Measurements of the neutron yield from a coaxial gun plasma

International Nuclear Information System (INIS)

Zolototrubov, I.M.; Krasnikov, A.A.; Kurishchenko, A.M.; Novikov, Yu.M.; Poryatuj, V.S.; Tolstolutskij, A.G.

1977-01-01

Neutron yield from deuterium plasma produced by a pulse coaxial accelerator was measured. The maximum neutron yield with 5 kj stored in a condenser battery is 3x10 6 neutron/pulse. The basis of the method of measuring neutron yield from the plasma was through the induced activity. It was shown that application of even a small uniform longitudinal magnetic field (up to 1 kOe) on the accelerator decreases several times the neutron yield. It is also shown that a small amount of stored discharge energy can produce high-temperature plasma at the output of pulse coaxial accelerator in the absense of the direct magnetic field. It is supposed that the reason for the reduction of neutron yield level in the case of applying the magnetic field is decreasing plasma density because of increasing the bunch cross-section

Measurements of radiative material properties for astrophysical plasmas

International Nuclear Information System (INIS)

Bailey, James E.

2010-01-01

The new generation of z-pinch, laser, and XFEL facilities opens the possibility to produce astrophysically-relevant laboratory plasmas with energy densities beyond what was previously possible. Furthermore, macroscopic plasmas with uniform conditions can now be created, enabling more accurate determination of the material properties. This presentation will provide an overview of our research at the Z facility investigating stellar interior opacities, AGN warm-absorber photoionized plasmas, and white dwarf photospheres. Atomic physics in plasmas heavily influence these topics. Stellar opacities are an essential ingredient of stellar models and they affect what we know about the structure and evolution of stars. Opacity models have become highly sophisticated, but laboratory tests have not been done at the conditions existing inside stars. Our research is presently focused on measuring Fe at conditions relevant to the base of the solar convection zone, where the electron temperature and density are believed to be 190 eV and 9 x 10 22 e/cc, respectively. The second project is aimed at testing atomic kinetics models for photoionized plasmas. Photoionization is an important process in many astrophysical plasmas and the spectral signatures are routinely used to infer astrophysical object's characteristics. However, the spectral synthesis models at the heart of these interpretations have been the subject of very limited experimental tests. Our current research examines photoionization of neon plasma subjected to radiation flux similar to the warm absorber that surrounds active galactic nuclei. The third project is a recent initiative aimed at producing a white dwarf photosphere in the laboratory. Emergent spectra from the photosphere are used to infer the star's effective temperature and surface gravity. The results depend on knowledge of H, He, and C spectral line profiles under conditions where complex physics such as quasi-molecule formation may be important. These

The healthiness of JT-60 ICRF antenna and development of its temperature measurement device

International Nuclear Information System (INIS)

Hiranai, Shinichi; Yokokura, Kenji; Moriyama, Shinichi; Sato, Tomio; Ishii, Kazuhiro; Fujii, Tsuneyuki

1998-03-01

Ion Cyclotron Range of Frequency (ICRF) heating system in JT-60 employs two antennas to couple RF power in the range of 100 MHz to the plasma. The antennas are installed in the vacuum vessel of JT-60, facing to the high temperature plasma. Due to the severe heat load from the plasma, parts of the antenna surface are suffering from melt. It is important to investigate the mechanism of the heat load and the melting. 'Temperature measurement for ICRF antenna surface' employing an infrared thermographic camera has been developed, in order to investigate the heat load to the antenna and to maintain the antenna available. We have succeeded in minimizing the melting damage of the antenna surface using the temperature measurement device. (author)

High Temperature Plasmas Theory and Mathematical Tools for Laser and Fusion Plasmas

CERN Document Server

Spatschek, Karl-Heinz

2012-01-01

Filling the gap for a treatment of the subject as an advanced course in theoretical physics with a huge potential for future applications, this monograph discusses aspects of these applications and provides theoretical methods and tools for their investigation. Throughout this coherent and up-to-date work the main emphasis is on classical plasmas at high-temperatures, drawing on the experienced author's specialist background. As such, it covers the key areas of magnetic fusion plasma, laser-plasma-interaction and astrophysical plasmas, while also including nonlinear waves and phenomena.

Effects of acute temperature change, confinement and housing on plasma corticosterone in water snakes, Nerodia sipedon (Colubridae: Natricinae).

Science.gov (United States)

Sykes, Kyle Lea; Klukowski, Matthew

2009-03-01

Body temperature affects many aspects of reptilian behavior and physiology, but its effect on hormonal secretion has been little studied, especially in snakes. Major objectives of this study were to determine if acute changes in body temperature during confinement influenced plasma corticosterone levels and if initial body temperatures upon capture in the field were related to baseline corticosterone levels in water snakes (Nerodia sipedon). Water snakes were bled upon capture in the field and after one hour of confinement in a cooled, control, or heated incubator. Since little is known about the potential metabolic changes in response to stress in reptiles, plasma triglyceride levels were also measured. Upon completion of the field study, snakes were housed for 5-8 days without food to determine the effect of chronic stress on both corticosterone and triglyceride levels. Plasma corticosterone concentrations were measured using enzyme-linked immunosorbant assay (ELISA) and plasma triglycerides were determined enzymatically. In the field, experimental alterations of body temperature during confinement had no effect on corticosterone levels. Similarly, there was no correlation between initial body temperature and baseline plasma corticosterone concentrations. However, post-confinement corticosterone levels were approximately three-times greater in females than males. Plasma triglyceride levels were not affected by temperature treatment, confinement, or sex. Compared to field values, both baseline and post-confinement corticosterone levels were elevated after the chronic stress of short-term laboratory housing but triglyceride levels decreased. Overall, these results indicate that sex but not body temperature has a major influence on the adrenocortical stress response in Nerodia sipedon.

Simultaneous temperature measurement of ionospheric plasma and neutral atmosphere with K-10-11 rocket

International Nuclear Information System (INIS)

Murasato, Yukio; Kaneko, Osamu; Sasaki, Susumu; Kawashima, Nobuki; Kibune, Tadashi.

1976-01-01

Ion temperature and neutral atmospheric temperature in lower ionospheric layer were measured by the ''Shadow Method'', which has been developed and improved by the authors. The principle of the method, which utilizes the fact that the shadow due to the reduction of density of medium behind on obstacle depends upon the flow velocity and the temperature of the medium, is briefly explained together with the apparatus used for the measurement. A pair of the Langmuir probes with the interval of 44 mm was used for the measurement of ion temperature. For the measurement of the neutral atmospheric temperature, its density was measured with the ionization gauge. The measuring system was mounted on the K-10-11 rocket, and launched from KSC at 2 p.m., September 24, 1975. Although the rocket itself reached its highest altitude of 196 km, the temperature measurement was performed between the altitude of 80 km and 140 km. The measured temperatures of ions, neutral atmosphere, and electrons are presented as the functions of altitude. It is confirmed that the temperatures of ions and neutral atmosphere are lower than that of electrons in that range of altitude. (Aoki, K.)

Microsecond Timescale Surface Temperature Measurements in Micro-Pulsed Plasma Thrusters

National Research Council Canada - National Science Library

Antonsen, Erik

2003-01-01

.... The diagnostic draws on heritage from the experimental dynamic crack propagation community which has used photovoltaic infrared detectors to measure temperature rise in materials in the process of fracture...

CH spectroscopy for carbon chemical erosion analysis in high density low temperature hydrogen plasma

NARCIS (Netherlands)

Westerhout, J.; Cardozo, N. J. L.; Rapp, J.; van Rooij, G. J.

2009-01-01

The CH A-X molecular band is measured upon seeding the hydrogen plasma in the linear plasma generator Pilot-PSI [electron temperature T-e=0.1-2.5 eV and electron density n(e)=(0.5-5) X 10(20) m(-3)] with methane. Calculated inverse photon efficiencies for these conditions range from 3 up to

Ion source plasma parameters measurement based on Langmuir probe with commercial frequency sweep

International Nuclear Information System (INIS)

Xie, Y.H.; Hu, C.D.; Liu, S.; Shong, S.H.; Jiang, C.C.; Liu, Z.M.

2010-01-01

Langmuir probe is one of the main diagnostic tools to measure the plasma parameters in the ion source. In this article, the commercial frequency power, which is sine wave of 50 Hz, was supplied on the Langmuir probe to measure the plasma parameters. The best feature of this probe sweep voltage is that it does not need extra design. The probe I-V characteristic curve can be got in less than 5 ms and the plasma parameters, the electron temperature and the electron density, varying with the time can be got in one plasma discharge of 400 ms.

Low-temperature plasma-induced antiproliferative effects on multi-cellular tumor spheroids

International Nuclear Information System (INIS)

Plewa, Joseph-Marie; Yousfi, Mohammed; Eichwald, Olivier; Merbahi, Nofel; Frongia, Céline; Ducommun, Bernard; Lobjois, Valérie

2014-01-01

Biomedical applications of low-temperature plasmas are of growing interest, especially in the field of plasma-induced anti-tumor effects. The present work is aimed at investigating the regionalized antiproliferative effects of low-temperature plasmas on a multicellular tumor spheroid (MCTS), a model that mimics the 3D organization and regionalization of a microtumor region. We report that a low-temperature plasma jet, using helium flow in open air, inhibits HCT116 colon carcinoma MCTS growth in a dose-dependent manner. This growth inhibition is associated with the loss of Ki67, and the regionalized accumulation of DNA damage detected by histone H2AX phosphorylation. This regionalized genotoxic effect leads to massive cell death and loss of the MCTS proliferative region. The use of reactive oxygen species (ROS), scavenger N-acetyl cysteine (NAC) and plasma-conditioned media demonstrate that the ROS generated in the media after exposure to low-temperature plasma play a major role in these observed effects. These findings strengthen the interest in the use of MCTS for the evaluation of antiproliferative strategies, and open new perspectives for studies dedicated to demonstrate the potential of low-temperature plasma in cancer therapy

Low-temperature plasma-induced antiproliferative effects on multi-cellular tumor spheroids

Science.gov (United States)

Plewa, Joseph-Marie; Yousfi, Mohammed; Frongia, Céline; Eichwald, Olivier; Ducommun, Bernard; Merbahi, Nofel; Lobjois, Valérie

2014-04-01

Biomedical applications of low-temperature plasmas are of growing interest, especially in the field of plasma-induced anti-tumor effects. The present work is aimed at investigating the regionalized antiproliferative effects of low-temperature plasmas on a multicellular tumor spheroid (MCTS), a model that mimics the 3D organization and regionalization of a microtumor region. We report that a low-temperature plasma jet, using helium flow in open air, inhibits HCT116 colon carcinoma MCTS growth in a dose-dependent manner. This growth inhibition is associated with the loss of Ki67, and the regionalized accumulation of DNA damage detected by histone H2AX phosphorylation. This regionalized genotoxic effect leads to massive cell death and loss of the MCTS proliferative region. The use of reactive oxygen species (ROS), scavenger N-acetyl cysteine (NAC) and plasma-conditioned media demonstrate that the ROS generated in the media after exposure to low-temperature plasma play a major role in these observed effects. These findings strengthen the interest in the use of MCTS for the evaluation of antiproliferative strategies, and open new perspectives for studies dedicated to demonstrate the potential of low-temperature plasma in cancer therapy.

Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

International Nuclear Information System (INIS)

Pedersen, N.F.; Soerensen, O.H.; Mygind, J.

1978-01-01

The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature T/sub c/ of the Sn films. The temperature dependence of the cosphi conductance is determined from the resonant response at the junction plasma frequency f/sub p/ as the temperature is decreased from T/sub c/. We used three different schemes for observation of the plasma oscillations: (a) second-harmonic generation (excitation at approx. 4.5 GHz, f/sub p/ approx. 4.5 GHz); (b) mixing (excitations at approx. 9 and approx. 18 GHz, f/sub p/ approx. 9 GHz); (c) parametric half-harmonic oscillation (excitation at approx. 18 GHz, f/sub p/ approx. 9 GHz). Measurements were possible in two temperature intervals; 0.994 or = T/T/sub c/ > or = 0.930, with the result that as the temperature was decreased the cosphi amplitude first increased from about zero to positive values and then at lower temperatures decreased approaching -1 at the lowest temperatures of the experiment

Non-equilibrium Microwave Plasma for Efficient High Temperature Chemistry.

Science.gov (United States)

van den Bekerom, Dirk; den Harder, Niek; Minea, Teofil; Gatti, Nicola; Linares, Jose Palomares; Bongers, Waldo; van de Sanden, Richard; van Rooij, Gerard

2017-08-01

A flowing microwave plasma based methodology for converting electric energy into internal and/or translational modes of stable molecules with the purpose of efficiently driving non-equilibrium chemistry is discussed. The advantage of a flowing plasma reactor is that continuous chemical processes can be driven with the flexibility of startup times in the seconds timescale. The plasma approach is generically suitable for conversion/activation of stable molecules such as CO2, N2 and CH4. Here the reduction of CO2 to CO is used as a model system: the complementary diagnostics illustrate how a baseline thermodynamic equilibrium conversion can be exceeded by the intrinsic non-equilibrium from high vibrational excitation. Laser (Rayleigh) scattering is used to measure the reactor temperature and Fourier Transform Infrared Spectroscopy (FTIR) to characterize in situ internal (vibrational) excitation as well as the effluent composition to monitor conversion and selectivity.

Development of a High Resolution X-Ray Imaging Crystal Spectrometer for Measurement of Ion-Temperature and Rotation-Velocity Profiles in Fusion Energy Research Plasmas

International Nuclear Information System (INIS)

Hill, K.W.; Bitter, M.L.; Broennimann, Ch.; Eikenberry, E.F.; Ince-Cushman, A.; Lee, S.G.; Rice, J.E.; Scott, S.; Barnsley, R.

2008-01-01

A new imaging high resolution x-ray crystal spectrometer (XCS) has been developed to measure continuous profiles of ion temperature and rotation velocity in fusion plasmas. Following proof-of-principle tests on the Alcator C-Mod tokamak and the NSTX spherical tokamak, and successful testing of a new silicon, pixilated detector with 1MHz count rate capability per pixel, an imaging XCS is being designed to measure full profiles of T i and ν φ on C-Mod. The imaging XCS design has also been adopted for ITER. Ion-temperature uncertainty and minimum measurable rotation velocity are calculated for the C-Mod spectrometer. The affects of x-ray and nuclear-radiation background on the measurement uncertainties are calculated to predict performance on ITER

Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

Science.gov (United States)

Kühn-Kauffeldt, M.; Marques, J.-L.; Forster, G.; Schein, J.

2013-10-01

The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned.

Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

International Nuclear Information System (INIS)

Kühn-Kauffeldt, M; Marques, J-L; Forster, G; Schein, J

2013-01-01

The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned

Ion temperature profiles along a hydrogen diagnostic beam in a TORE SUPRA tokamak plasma

International Nuclear Information System (INIS)

Romannikov, A.; Petrov, Yu.; Platts, P.; Khess, V.; Khutter, T.; Farzhon, Zh.; Moro, F.

2002-01-01

By means of corpuscular diagnostics one studies temperature of ions along a diagnostic hydrogen beam. Paper presents comparison of temperature of plasma (deuterium) basic ions measures by means of the active corpuscular diagnostics with temperature of C + carbon ions along a beam. One studies behavior peculiarities of T i ion temperature profiles for TORE-SUPRA different modes, such as: formation of plane and even hollow T i profiles for ohmic modes, variation of T i profiles under operation of an ergodic diverter, difference of temperature of basic ions measured by means of the active corpuscular diagnostics from C +5 temperature. Paper offers clear explanation of these peculiarities [ru

Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems

Energy Technology Data Exchange (ETDEWEB)

Lai, J.; Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616 (United States)

2014-03-15

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T{sub e} and n{sub e} fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ∼60 000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50–75 GHz), significant improvement of noise temperature from the current 60 000 K to measured 4000 K has been obtained.

Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems.

Science.gov (United States)

Lai, J; Domier, C W; Luhmann, N C

2014-03-01

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T(e) and n(e) fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ~60,000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50-75 GHz), significant improvement of noise temperature from the current 60,000 K to measured 4000 K has been obtained.

Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems

International Nuclear Information System (INIS)

Lai, J.; Domier, C. W.; Luhmann, N. C.

2014-01-01

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T e and n e fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ∼60 000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50–75 GHz), significant improvement of noise temperature from the current 60 000 K to measured 4000 K has been obtained

Properties of plasma sheath with ion temperature in magnetic fusion devices

International Nuclear Information System (INIS)

Liu Jinyuan; Wang Feng; Sun Jizhong

2011-01-01

The plasma sheath properties in a strong magnetic field are investigated in this work using a steady state two-fluid model. The motion of ions is affected heavily by the strong magnetic field in fusion devices; meanwhile, the effect of ion temperature cannot be neglected for the plasma in such devices. A criterion for the plasma sheath in a strong magnetic field, which differs from the well-known Bohm criterion for low temperature plasma sheath, is established theoretically with a fluid model. The fluid model is then solved numerically to obtain detailed sheath information under different ion temperatures, plasma densities, and magnetic field strengths.

Measurement of toroidal and poloidal plasma rotation in TCA

International Nuclear Information System (INIS)

Duval, B.P.; Joye, B.; Marchal, B.

1991-01-01

With optimal observation geometry we have measured both the toroidal and poloidal rotation velocities in the edge and in the bulk of the TCA plasma. Regular calibration and correction for variations in the spectrometer temperature permitted a measurement with an error of ∼0.5 km/s which is an order of magnitude smaller than the range of measured velocities. In general, changes in the velocities are observed to be stronger and faster in the plasma edge than in the plasma bulk. With increasing density, the toroidal velocity is observed to change sign and follow the plasma density, while the poloidal velocity increases. These two effects lead to an increase in the absolute value of the radial electric field. With very strong gas puffing, the toroidal velocity is observed to again reverse and tend to zero, an effect which is stronger as the gradient of the density ramp is increased. Comparison between gas puffing and high power AWH does not show a significant difference in the radial electric field that could be responsible for the large associated density rise, which still remains unexplained. (author) 4 figs., 2 refs

Determination of Ar metastable atom densities in Ar and Ar/H2 inductively coupled low-temperature plasmas

International Nuclear Information System (INIS)

Fox-Lyon, N; Knoll, A J; Oehrlein, G S; Franek, J; Demidov, V; Koepke, M; Godyak, V

2013-01-01

Ar metastable atoms are important energy carriers and surface interacting species in low-temperature plasmas that are difficult to quantify. Ar metastable atom densities (N Ar,m ) in inductively coupled Ar and Ar/H 2 plasmas were obtained using a model combining electrical probe measurements of electron density (N e ) and temperature (T e ), with analysis of spectrally resolved Ar plasma optical emission based on 3p → 1s optical emission ratios of the 419.8 nm line to the 420.1 nm line. We present the variation of N Ar,m as the Ar pressure and the addition of H 2 to Ar are changed comparatively to recent adsorption spectroscopy measurements. (paper)

Measured Temperature Dependence of the cos-phi Conductance in Josephson Tunnel Junctions

DEFF Research Database (Denmark)

Sørensen, O. H.; Mygind, Jesper; Pedersen, Niels Falsig

1977-01-01

The temperature dependence of the cosϕ conductance in Sn-O-Sn Josephson tunnel junctions has been measured just below the critical temperature, Tc. From the resonant microwave response at the junction plasma frequency as the temperature is decreased from Tc it is deduced that the amplitude of the...

Electron density and temperature profile diagnostics for C-2 field reversed configuration plasmas

Energy Technology Data Exchange (ETDEWEB)

Deng, B. H.; Kinley, J. S.; Schroeder, J. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States)

2012-10-15

The 9-point Thomson scattering diagnostic system for the C-2 field reversed configuration plasmas is improved and the measured electron temperature profiles are consistent with theoretical expectations. Rayleigh scattering revealed a finite line width of the ruby laser emission, which complicates density calibration. Taking advantage of the plasma wobble motion, density profile reconstruction accuracy from the 6-chord two-color CO{sub 2}/HeNe interferometer data is improved.

Role of atom--atom inelastic collisions in two-temperature nonequilibrium plasmas

International Nuclear Information System (INIS)

Kunc, J.A.

1987-01-01

The contribution of inelastic atom--atom collisions to the production of electrons and excited atoms in two-temperature (with electron temperature T/sub e/, atomic temperature T/sub a/, and atomic density N/sub a/), steady-state, nonequilibrium atomic hydrogen plasma is investigated. The results are valid for plasmas having large amounts of atomic hydrogen as one of the plasma components, so that e--H and H--H inelastic collisions and interaction of these atoms with radiation dominate the production of electrons and excited hydrogen atoms. Densities of electrons and excited atoms are calculated in low-temperature plasma, with T/sub e/ and T/sub a/≤8000 K and 10 16 cm -3 ≤N/sub a/≤10 18 cm -3 , and with different degrees of the reabsorption of radiation. The results indicate that inelastic atom--atom collisions are important for production of electrons and excited atoms in partially ionized plasmas with medium and high atomic density and temperatures below 8000 K

Josephson plasma resonance in vortex filament state of high temperature superconductors

International Nuclear Information System (INIS)

Matsuda, Yuji; Gaifullin, M.B.

1996-01-01

High temperature superconductors have the crystalline structure in which two-dimensional CuO 2 planes are piled in layers, consequently, the anisotropy of electroconductivity arises, and this brings about stable and low energy Josephson plasma in superconducting state. Also as to the vortex filament state of high temperature superconductors, the effect of thermal fluctuation due to low dimensionality, short coherence length and high transition temperature becomes conspicuous. In reality, these plasma and vortex filament state are related closely. Light reflection and plasma edge in superconducting state, Josephson plasma resonance in the vortex filament state of BiO 2 Sr 2 CaCu 2 O 8+δ , the plasma vibration in Josephson junction, Josephson plasma in magnetic field, Josephson plasma in the liquid state of vortex filament, Josephson plasma in the solid state of vortex filament, and Josephson plasma in parallel magnetic field are reported. The Josephson plasma resonance is the experimental means for exploring vortex filament state from microscopic standpoint, and its development hereafter is expected. (K.I.)

Active silicon x-ray for measuring electron temperature

International Nuclear Information System (INIS)

Snider, R.T.

1994-07-01

Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

Development of plasma diagnostics technologies - Measurement of transport= parameters in tokamak edge plasma by using electric transport probes

Energy Technology Data Exchange (ETDEWEB)

Chung, Kyu Sun; Chang, Do Hee; Sim, Yeon Gun; Kim, Jin Hee [Hanyang University, Seoul (Korea, Republic of)

1995-08-01

Electric transport probe system is developed for the measurement of electron temperature, floating potential, plasma density and flow velocity of= edge plasmas in the KT-2 medium size tokamak. Experiments have been performed in KT-1 small size tokamak. Electric transport probe is composed of a single probe(SP) and a Mach probe (MP). SP is used for the measurements of electron density, floating potential, and plasma density and measured values are {approx} 3*10{sup 11}/cm{sup -3}, -20 volts, 15 {approx} 25 eV. For the most discharges, respectively. MP is for the measurements of toroidal(M{sub T}) and poloidal(M{sub P}) flow velocities, and density, which are M{sub T} {approx_equal} .0.85, M{sub P} {approx_equal}. 0.17, n. {approx_equal} 2.1*10{sup 11} cm{sup -3}, respectively. A triple probe is also developed for the direct reading of T{sub e} and n{sub e}, and is used for DC, RF, and RF+DC plasma in APL of Hanyang university. 38 refs., 36 figs. (author)

Plan of measurement experiment of correlation between ion beam and plasma

Energy Technology Data Exchange (ETDEWEB)

Oguri, Yoshiyuki; Abe, Satoru; Sakumi, Akira; Okazaki, Hisashi; Watanabe, Takeshi [Tokyo Inst. of Tech. (Japan). Research Lab. for Nuclear Reactors

1996-12-01

The Research Laboratory, for Nuclear Reactors, Tokyo Institute of Technology has conducted experimental study on accelerating structure and beam behavior of high intensity heavy ion accelerator for a beam driver and its computer simulation study as a circle of fundamental study of the heavy ion inertial nuclear fusion. From last fiscal year, a preliminary study for measuring the correlation between beam and plasma using low speed heavy ion beam from 1.7 MV tandem accelerator was begun. As a result, a possibility of forming a plasma target with above 10 (exp 17)/cu cm in free electron density and about 100 ns in life possible to supply to measurement of the correlation between beam and plasma was obtained by formation of laser plasma target and development of diagnostic measurement system. According to the preliminary calculation, it is expected to be larger charging state of ion passing through plasma than that in normal temperature target, and stoppability is presumed to increase largely and to apply to electron stopper for accelerator. And, a plan of time resolution measurement of energy loss of beam passed through plasma target using magnetic field type spectrometer and high speed plastic scintillator is also preceeding. (G.K.)

Production of a large diameter ECR plasma with low electron temperature

International Nuclear Information System (INIS)

Koga, Mayuko; Hishikawa, Yasuhiro; Tsuchiya, Hayato; Kawai, Yoshinobu

2006-01-01

A large diameter plasma over 300 mm in diameter is produced by electron cyclotron resonance (ECR) discharges using a cylindrical vacuum chamber of 400 mm in inner diameter. It is found that the plasma uniformity is improved by adding the nitrogen gas to pure Ar plasma. The electron temperature is decreased by adding the nitrogen gas. It is considered that the electron energy is absorbed in the vibrational energy of nitrogen molecules and the electron temperature decreases. Therefore, the adjunction of the nitrogen gas is considered to be effective for producing uniform and low electron temperature plasma

Experimental Research of Inactivation Effect of Low-Temperature Plasma on Bacteria

International Nuclear Information System (INIS)

Shi Xingmin; Yuan Yukang; Sun Yanzhou; Yuan Wang; Fengling, Peng; Qiu Yuchang

2006-01-01

The killing logarithms index in killing a vegetative form in an explosure of about 90 s and a spore in an explosure of about 120 s, by using a low-temperature plasma produced by dielectric barrier discharge (DBD), reached 5. The speed in killing the strains tested, by using a low-temperature plasma, was the highest with E. Coli, then S. Aureus and B. Subtilis var niger spore. The results of the scanning electron microscope showed that the low-temperature plasma destroyed the outer structure of the bacteria and that the vegetative form was more susceptible to the inactivation effect of the low-temperature plasma than was the spore. This indicated that the effects of the high voltage and high velocity particle flow, in plasma, penetrating through the outer structure of the bacteria might play a dominant role during the inactivation of the bacteria

A two-temperature chemical non-equilibrium modeling of DC arc plasma

International Nuclear Information System (INIS)

Qian Haiyang; Wu Bin

2011-01-01

To a better understanding of non-equilibrium characteristics of DC arc plasma,a two-dimensional axisymmetric two-temperature chemical non-equilibrium (2T-NCE) model is applied for direct current arc argon plasma generator with water-cooled constrictor at atmospheric pressure. The results show that the electron temperature and heavy particle temperature has a relationship under different working parameters, indicating that DC arc plasma has a strong non-equilibrium characteristic, and the variation is obvious. (authors)

Characterization of Electron Temperature and Density Profiles of Plasmas Produced by Nike KrF Laser for Laser Plasma Instability (LPI) Research

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Phillips, L.; Obenschain, S. P.; Schmitt, A. J.; Kehne, D. M.; Chan, L.-Y.; Serlin, V.

2011-10-01

Previous experiments with Nike KrF laser (λ = 248 nm , Δν ~ 1 THz) observed LPI signatures near quarter critical density (nc / 4) in CH plasmas, however, detailed measurement of the temperature (Te) and density (ne) profiles was missing. The current Nike LPI campaign will perform experimental determination of the plasma profiles. A side-on grid imaging refractometer (GIR) is the main diagnostic to resolve Te and ne in space taking 2D snapshots of probe laser (λ = 266 nm , Δt = 8 psec) beamlets (50 μm spacing) refracted by the plasma at laser peak time. Ray tracing of the beamlets through hydrodynamically simulated (FASTRAD3D) plasma profiles estimates the refractometer may access densities up to ~ 0 . 2nc . With the measured Te and ne profiles in the plasma corona, we will discuss analysis of light data radiated from the plasmas in spectral ranges relevant to two plasmon decay and convective Raman instabilities. Validity of the (Te ,ne) data will also be discussed for the thermal transport study. Work supported by DoE/NNSA and ONR and performed at NRL.

Plasma interaction with liquid lithium: Measurements of retention and erosion

Energy Technology Data Exchange (ETDEWEB)

Baldwin, M.J. E-mail: mbaldwin@ferp.ucsd.edu; Doerner, R.P.; Luckhardt, S.C.; Seraydarian, R.; Whyte, D.G.; Conn, R.W

2002-11-01

This paper reports on recent studies of high flux deuterium and helium plasma interaction with liquid lithium in the Pisces-B edge plasma simulator facility. Deuterium retention is explored as a function of plasma ion fluence in the range 6x10{sup 19}-4x10{sup 22} atoms cm{sup -2} and exposure temperatures of 523-673 K. The results are consistent with full uptake of the deuterium ions incident on the liquid metal surface, independent of the temperature of the liquid lithium. Full uptake continues until the sample is volumetrically converted to lithium deuteride. Helium retention is not observed for fluences up to 5x10{sup 21} He atoms cm{sup -2}. Measurements of the erosion of lithium are found to be consistent with physical sputtering for the lithium solid phase. However, a mechanism that provides an increased evaporative-like yield and is related to ion impact events on the surface, dominates during the liquid phase leading to an enhanced loss rate for liquid lithium that is greater than the expected loss rate due to evaporation at elevated temperatures. Further, the material loss rate is found to depend linearly on the incident ion flux, even at very high temperature.

Development of plasma bolometers using fiber-optic temperature sensors

Energy Technology Data Exchange (ETDEWEB)

Reinke, M. L., E-mail: reinkeml@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Han, M.; Liu, G. [University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States); Eden, G. G. van [Dutch Institute for Fundamental Energy Research, De Zaale 20, 5612 AJ Eindhoven (Netherlands); Evenblij, R.; Haverdings, M. [Technobis, Pyrietstraat 2, 1812 SC Alkmaar (Netherlands); Stratton, B. C. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 (United States)

2016-11-15

Measurements of radiated power in magnetically confined plasmas are important for exhaust studies in present experiments and expected to be a critical diagnostic for future fusion reactors. Resistive bolometer sensors have long been utilized in tokamaks and helical devices but suffer from electromagnetic interference (EMI). Results are shown from initial testing of a new bolometer concept based on fiber-optic temperature sensor technology. A small, 80 μm diameter, 200 μm long silicon pillar attached to the end of a single mode fiber-optic cable acts as a Fabry–Pérot cavity when broadband light, λ{sub o} ∼ 1550 nm, is transmitted along the fiber. Changes in temperature alter the optical path length of the cavity primarily through the thermo-optic effect, resulting in a shift of fringes reflected from the pillar detected using an I-MON 512 OEM spectrometer. While initially designed for use in liquids, this sensor has ideal properties for use as a plasma bolometer: a time constant, in air, of ∼150 ms, strong absorption in the spectral range of plasma emission, immunity to local EMI, and the ability to measure changes in temperature remotely. Its compact design offers unique opportunities for integration into the vacuum environment in places unsuitable for a resistive bolometer. Using a variable focus 5 mW, 405 nm, modulating laser, the signal to noise ratio versus power density of various bolometer technologies are directly compared, estimating the noise equivalent power density (NEPD). Present tests show the fiber-optic bolometer to have NEPD of 5-10 W/m{sup 2} when compared to those of the resistive bolometer which can achieve <0.5 W/m{sup 2} in the laboratory, but this can degrade to 1-2 W/m{sup 2} or worse when installed on a tokamak. Concepts are discussed to improve the signal to noise ratio of this new fiber-optic bolometer by reducing the pillar height and adding thin metallic coatings, along with improving the spectral resolution of the interrogator.

Integrated heat transport simulation of high ion temperature plasma of LHD

International Nuclear Information System (INIS)

Murakami, S.; Yamaguchi, H.; Sakai, A.

2014-10-01

A first dynamical simulation of high ion temperature plasma with carbon pellet injection of LHD is performed by the integrated simulation GNET-TD + TASK3D. NBI heating deposition of time evolving plasma is evaluated by the 5D drift kinetic equation solver, GNET-TD and the heat transport of multi-ion species plasma (e, H, He, C) is studied by the integrated transport simulation code, TASK3D. Achievement of high ion temperature plasma is attributed to the 1) increase of heating power per ion due to the temporal increase of effective charge, 2) reduction of effective neoclassical transport with impurities, 3) reduction of turbulence transport. The reduction of turbulence transport is most significant contribution to achieve the high ion temperature and the reduction of the turbulent transport from the L-mode plasma (normal hydrogen plasma) is evaluated to be a factor about five by using integrated heat transport simulation code. Applying the Z effective dependent turbulent reduction model we obtain a similar time behavior of ion temperature after the C pellet injection with the experimental results. (author)

Ion temperature measurements in the scrape-off layer of the Tore Supra Tokamak

International Nuclear Information System (INIS)

Kocan, M.

2009-10-01

The thesis describes measurements of the scrape-off layer (SOL) ion temperature T i with a retarding field analyzer (RFA) in the limiter tokamak Tore Supra. Considerable emphasis is placed on study of the instrumental effects of RFAs and their influence on T i measurements. In general, the influence of instrumental effects on T i measurements is found to be relatively small. The instrumental study is followed by systematic measurements of T i (as well as other parameters) in the Tore Supra SOL. This includes the scaling of SOL temperatures and electron density with the main plasma parameters (such as the plasma density, toroidal magnetic field, working gas, and the radiated power fraction). Except at very high densities or in detached plasmas, SOL T i is found to be higher than T e by up to a factor of 7. While SOL T i is found to vary by almost two orders of magnitude, following the variation of the core temperatures, SOL T e changes only little and seems to be decoupled from the core plasma. The first continuous T i /T e profile from the edge of the confined plasma into the SOL is constructed using data from different tokamaks. It is shown that T i /T e > 1 in the SOL but also in the confined plasma, and increases with radius. The first evidence of poloidal asymmetry of the radial ion and electron energy transport in the SOL is reported. Implications for ITER start-up phase are discussed. Correlation of the asymmetries of SOL T i and T e measured from both directions along the magnetic field lines with changes of the parallel Mach number is studied. SOL T i was measured for the first time in Tore Supra by charge exchange recombination spectroscopy (CXRS) and compared to RFA data. A factor of 4 higher T i measured by CXRS is a subject of further analysis. (A.C.)

Ion Spin-Up, Temperature, and Flow Measurements in the TCSU Experiment

Science.gov (United States)

Deards, C. L.; Grossnickle, J. A.; Steinhauer, L. C.; Melnik, P. A.; Milroy, R. D.

2009-11-01

The Translation, Confinement, and Sustainment Upgrade (TCSU) experiment employs a bakeable ultra-high vacuum chamber to reduce impurities and overall recycling. In recent experiments with Ti gettering applied to the plasma tube, radiation from impurities was dramatically reduced and recycling was almost eliminated. Ion temperature and azimuthal rotation velocities data from the resulting lower density, higher temperature FRC will be presented. The data comes from Doppler-broadening and Doppler-shifted measurements of Si III, C III, and O III, the dominant impurities in the TCSU plasma. Additionally, plans and initial data will be presented on azimuthal and poloidal velocity shear. Velocity shear is thought to improve stability and transport. All data measurements are made using an Acton Research SpectraPro 500i Czerny-Turney type spectrograph.

From stellar plasmas to laboratory plasmas: application to X and XUV opacity measurements

International Nuclear Information System (INIS)

Loisel, G.

2011-01-01

The general context of this thesis is the one of radiative properties of high energy density matter. Energy densities involved (>10 11 J/cm 3 ) implies that a large part of energy exchange goes through radiation-matter interactions. My studies deal with spectral opacity, a fundamental parameter for modelling stellar interiors and constitute a propitious observable to experimental tests of theoretical descriptions of hot and dense plasmas physics. Although the main application of my work is stellar plasmas it can be useful for plasma diagnostics in inertial confinement fusion. My work activities are centred on the experimental study of opacities of plasmas at local thermodynamic equilibrium for temperature conditions of a few tens eV (a few 100000 K) and a few mg/cm 3 in matter density. Plasmas are obtained in conditions as homogenous as possible using the radiative heating of a laser-irradiated cavity. Heating is provided through a laser beam of high energy (100-300 J) and with relatively long pulse duration of a few nanosecond. For such measurements we could benefit from the LULI lasers configuration coupling the nanosecond beam with a picosecond one used to perform on a short duration the measurement of the plasma transmission. The use of short pulse laser to produce a short time radiography beam was a first achievement for this kind of experience. In the spectral range of keV photons, absorbing transitions 2p-3d or 3d-4f of elements of moderate or high atomic number have been probed. They present absorption structures which shape results mainly of the competition between spin-orbit splitting and statistical broadening effects. It appeared that this competition depends strongly on the atomic number Z. Thus for similar plasma parameters we explored opacities of Iron, Nickel, Copper and Germanium (Z around 30) in a first series of measurement and the one of Barium, Samarium and Gadolinium (Z around 60) in a second campaign

Thomson scattering measurements in atmospheric plasma jets

International Nuclear Information System (INIS)

Gregori, G.; Schein, J.; Schwendinger, P.; Kortshagen, U.; Heberlein, J.; Pfender, E.

1999-01-01

Electron temperature and electron density in a dc plasma jet at atmospheric pressure have been obtained using Thomson laser scattering. Measurements performed at various scattering angles have revealed effects that are not accounted for by the standard scattering theory. Differences between the predicted and experimental results suggest that higher order corrections to the theory may be required, and that corrections to the form of the spectral density function may play an important role. copyright 1999 The American Physical Society

Thermophysical property measurement at high temperatures by laser-produced plasmas

International Nuclear Information System (INIS)

Kim, Y.W.

1993-01-01

Excitation by a high-power laser pulse of a material surface generates a sequence of plasma, fluid flow, and acoustic events. These are well separated in time, and their detection and analysis can lead to determination of material properties of the condensed phase target. We have developed a new methodology for real-time determination of molten metal composition by time-resolved spectroscopy of laser-produced plasmas (LPP). If the laser pulse is shaped in such a way that the movement of the bulk surface due to evaporation is kept in pace with the thermal diffusion front advancing into the interior of the target, the LPP plume becomes representative of the bulk in elemental composition. In addition, the mass loss due to LPP ablation is very well correlated with the thermal diffusivity of the target matter. For several elemental solid specimens, we show that the product of the ablation thickness and heat of formation is proportional to the thermal diffusivity per unit molecular weight. Such measurements can be extended to molten metal specimens if the mass loss by ablation, density, heat of formation, and molecular weight can be determined simultaneously. The results from the solid specimen and the progress with a levitation-assisted molten metal experiment are presented

Soft X-ray measurements for investigating the plasma focus dynamics

International Nuclear Information System (INIS)

Nahrath, B.

In a Mather-type plasma focus short time soft x-ray pictures are taken by means of a double pinhole camera equipped with a pulsed channel plate and two different filters to study the local development of electron temperatures Tsub(e) with time resolution of 3 ns. Up to the maximum compression the measured Tsub(e) are roughly in accordance with the results of MHD-calculations. During a later phase, characterized by the occurence of m=O-instabilities, localized plasma regions with high densities and high electron temperatures Tsub(e) of about 600 eV (up to 1000 eV) are observed. Using the channel plate technique with increased sensivity a slowly decaying plasma with local Tsub(e)-values of about 300 eV and large diffuse structures is identified for several hundred nanoseconds. During this 'late phase' of the focus most of the neutron emission takes place. There is no correlation between the value of Tsub(e) and the rate of neutron emission. (orig.) [de

Characteristics of short distance field of a source radiating at electronic frequencies in a ionospheric plasma. Applications to density and electron temperature measurement by mutual impedance probe

International Nuclear Information System (INIS)

Debrie, R.

1983-06-01

Realization of a new type of radio-frequency probe, the mutual-impedance probe (or the quadrupole probe) is developed. Theoretical results obtained with a cold plasma description of the ionized medium with static magnetic field. Transfer impedance between two dipoles in an homogeneous hot and isotope plasma is then calculated. In equatorial ionosphere, measurements made by the H.F. quadrupole probe, in the Veronique rocket, during the Cisaspe experiment, have been interpreted with this hot plasma theory. The influence of a plasma drift with respect to the emitter dipole is analyzed. The influence of a static magnetic field in hot and homogeneous plasma, on the frequency response curve of the mutual impedance is studied. For, in ionospheric plasmas of auroral and polar zones, the earth magnetic field is no more negligible and gives to the plasma dielectric, strongly anisotropic, properties well described by the microscopic theory in hot magnetoplasma. The space time fast evolution of characteristics of plasma encountered in space experiments has been shown up with a new method of measurement the self-oscillating quadrupole probe. The work synthesis is put in a concrete form on the polar satellite Aureol-3 the first results of which are presented. This satellite allows a precise study of ionosphere auroral zones. At last, it is shown that methods developed for electron density and temperature measurements can be transposed in low frequency. In this case, measurements with quadrupole probe allow to get the ion average mass by lower hybrid frequency excitation [fr

Measurement of toroidal plasma current in RF heated helical plasmas

International Nuclear Information System (INIS)

Besshou, Sakae

1993-01-01

This report describes the measurement of toroidal plasma current by a semiflexible Rogowski coil in a helical vacuum chamber. A Rogowski coil measures the toroidal plasma current with a resolution of 0.1 kA, frequency range of up to 1 kHz and sensitivity of 6.5 x 10 -9 V · s/A. We measured the spontaneous toroidal plasma current (from -1.2 to +1.2 kA) under electron cyclotron resonance heating at 0.94 T toroidal field in the Heliotron-E device. We found that the measured direction of toroidal plasma current changes its sign as in the predicted behavior of a neoclassical diffusion-driven bootstrap current, depending on the horizontal position of the plasma column. We explain the observed plasma currents in terms of the compound phenomenon of an ohmic current and a neoclassical diffusion-driven current. The magnitude of the neoclassical current component is smaller than the value predicted by a collisionless neoclassical theory. (author)

Biomedical applications using low temperature plasma technology

International Nuclear Information System (INIS)

Dai Xiujuan; Jiang Nan

2006-01-01

Low temperature plasma technology and biomedicine are two different subjects, but the combination of the two may play a critical role in modern science and technology. The 21 st century is believed to be a biotechnology century. Plasma technology is becoming a widely used platform for the fabrication of biomaterials and biomedical devices. In this paper some of the technologies used for material surface modification are briefly introduced. Some biomedical applications using plasma technology are described, followed by suggestions as to how a bridge between plasma technology and biomedicine can be built. A pulsed plasma technique that is used for surface functionalization is discussed in detail as an example of this kind of bridge or combination. Finally, it is pointed out that the combination of biomedical and plasma technology will be an important development for revolutionary 21st century technologies that requires different experts from different fields to work together. (authors)

Temperature dependence of the cosphi conductance in Josephson tunnel junctions determined from plasma resonance experiments

DEFF Research Database (Denmark)

Pedersen, Niels Falsig; Sørensen, O. H.; Mygind, Jesper

1978-01-01

The microwave response at 9 GHz of Sn-O-Sn tunnel-junction current biased at zero dc voltage has been measured just below the critical temperature Tc of the Sn films. The temperature dependence of the cosφ conductance is determined from the resonant response at the junction plasma frequency fp...

Atomic and ionic density measurement by laser absorption spectroscopy of magnetized or non-magnetized plasmas

International Nuclear Information System (INIS)

Le Gourrierec, P.

1989-11-01

Laser absorption spectroscopy is an appreciated diagnostic in plasma physics to measure atomic and ionic densities. We used it here more specifically on metallic plasmas. Firstly, a uranium plasma was created in a hollow cathode. 17 levels of U.I and U.II (12 for U.I and 5 for U.II) are measured by this method. The results are compared with the calculated levels of two models (collisional-radiative and LTE). Secondly, the theory of absorption in presence of a magnetic field is recalled and checked. Then, low-density magnetized plasma produced on our ERIC experiment (acronym for Experiment of Resonance Ionic Cyclotron), have been diagnosed successfully. The use of this technique on a low density plasma has not yet been published to our knowledge. The transverse temperature and the density of a metastable atomic level of a barium plasma has been derived. The evolution of a metastable ionic level of this element is studied in terms of two source parameters (furnace temperature and injected hyperfrequency power) [fr

Physics and engineering of singlet delta oxygen production in low-temperature plasma

International Nuclear Information System (INIS)

Ionin, A A; Kochetov, I V; Napartovich, A P; Yuryshev, N N

2007-01-01

An overview is presented of experimental and theoretical research in the field of physics and engineering of singlet delta oxygen (SDO) production in low-temperature plasma of various electric discharges. Attention is paid mainly to the SDO production with SDO yield adequate for the development of an electric discharge oxygen-iodine laser (DOIL). The review comprises a historical sketch describing the main experimental results on SDO physics in low-temperature plasma obtained since the first detection of SDO in electric discharge in the 1950s and the first attempt to launch a DOIL in the 1970s up to the mid-1980s when several research groups started their activity aimed at DOIL development, stimulated by success in the development of a chemical oxygen-iodine laser (COIL). A detailed analysis of theoretical and experimental research on SDO production in electric discharge from the mid-1980s to the present, when the first DOIL has been launched, is given. Different kinetic models of oxygen low-temperature plasma are compared with the model developed by the authors. The latter comprises electron kinetics based on the accompanying solution of the electron Boltzmann equation, plasma chemistry including reactions of excited molecules and numerous ion-molecular reactions, thermal energy balance and electric circuit equation. The experimental part of the overview is focused on the experimental methods of SDO detection including experiments on the measurements of the Einstein coefficient for SDO transition a 1 Δ g - X 3 Σ g - and experimental procedures of SDO production in self-sustained and non-self-sustained discharges and analysis of different plasma-chemical processes occurring in oxygen low-temperature plasma which brings limitation to the maximum SDO yield and to the lifetime of the SDO in an electric discharge and its afterglow. Quite recently obtained results on gain and output characteristics of DOIL and some projects aimed at the development of high-power DOIL

In-situ monitoring of etching of bovine serum albumin using low-temperature atmospheric plasma jet

Science.gov (United States)

Kousal, J.; Shelemin, A.; Kylián, O.; Slavínská, D.; Biederman, H.

2017-01-01

Bio-decontamination of surfaces by means of atmospheric pressure plasma is nowadays extensively studied as it represents promising alternative to commonly used sterilization/decontamination techniques. The non-equilibrium atmospheric pressure plasmas were already reported to be highly effective in removal of a wide range of biological residual from surfaces. Nevertheless the kinetics of removal of biological contamination from surfaces is still not well understood as the majority of performed studies were based on ex-situ evaluation of etching rates, which did not allow investigating details of plasma action on biomolecules. This study therefore presents a real-time, in-situ ellipsometric characterization of removal of bovine serum albumin (BSA) from surfaces by low-temperature atmospheric plasma jet operated in argon. Non-linear and at shorter distances between treated samples and nozzle of the plasma jet also non-monotonic dependence of the removal rate on the treatment duration was observed. According to additional measurements focused on the determination of chemical changes of treated BSA as well as temperature measurements, the observed behavior is most likely connected with two opposing effects: the formation of a thin layer on the top of BSA deposit enriched in inorganic compounds, whose presence causes a gradual decrease of removal efficiency, and slight heating of BSA that facilitates its degradation and volatilization induced by chemically active radicals produced by the plasma.

Determination of gas temperature and thermometric species in inductively coupled plasmas by emission and diode laser absorption

International Nuclear Information System (INIS)

Bol'shakov, Alexander A; Cruden, Brett A; Sharma, Surendra P

2004-01-01

A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission source for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3%, 45%, and 90% N 2 in Ar) at pressures of 0.5-70 Pa and inductive powers of 100 and 300 W. The results were compared to the rotational temperature derived from the N 2 emission at the (0,0) vibrational transition of the C 3 Π u -B 3 Π g system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar * and N 2 *) that varied depending on the conditions. A two-dimensional, three-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable us to track the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma

Determination of gas temperature and thermometric species in inductively coupled plasmas by emission and diode laser absorption

Energy Technology Data Exchange (ETDEWEB)

Bol' shakov, Alexander A; Cruden, Brett A; Sharma, Surendra P [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2004-11-01

A vertical cavity surface-emitting laser diode (VCSEL) was used as a spectrally tunable emission source for measurements of the radial-integrated gas temperature inside an inductively coupled plasma reactor. The data were obtained by profiling the Doppler-broadened absorption of metastable Ar atoms at 763.51 nm in argon and argon/nitrogen plasmas (3%, 45%, and 90% N{sub 2} in Ar) at pressures of 0.5-70 Pa and inductive powers of 100 and 300 W. The results were compared to the rotational temperature derived from the N{sub 2} emission at the (0,0) vibrational transition of the C {sup 3}{pi}{sub u}-B {sup 3}{pi} {sub g} system. The differences in integrated rotational and Doppler temperatures were attributed to non-uniform spatial distributions of both temperature and thermometric species (Ar{sup *} and N{sub 2}*) that varied depending on the conditions. A two-dimensional, three-temperature fluid plasma simulation was employed to explain these differences. This work should facilitate further development of a miniature sensor for non-intrusive acquisition of data (temperature and densities of multiple plasma species) during micro- and nano-fabrication plasma processing, thus enabling diagnostic-assisted continuous optimization and advanced control over the processes. Such sensors would also enable us to track the origins and pathways of damaging contaminants, thereby providing real-time feedback for adjustment of processes. Our work serves as an example of how two line-of-sight integrated temperatures derived from different thermometric species make it possible to characterize the radial non-uniformity of the plasma.

The inductively coupled plasma as a source for the measurement of fundamental spectroscopic constants

International Nuclear Information System (INIS)

Farnsworth, P.B.

1993-01-01

Inductively coupled plasmas (ICPs) are stable, robust sources for the generation of spectra from neutral and singly ionized atoms. They are used extensively for analytical spectrometry, but have seen limited use for the measurement of fundamental spectroscopic constants. Several properties of the ICP affect its suitability for such fundamental measurements. They include: spatial structure, spectral background, noise characteristics, electron densities and temperatures, and the state of equilibrium in the plasma. These properties are particularly sensitive to the means by which foreign atoms are introduced into the plasma. With some departures from the operating procedures normally used in analytical measurements, the ICP promise to be a useful source for the measurement of fundamental atomic constants. (orig.)

Papers presented at the Tenth Topical Conference on High-Temperature Plasma Diagnostics

International Nuclear Information System (INIS)

1994-01-01

This report contains papers on the following topics: Effects of limited spatial resolution on fluctuation measurements; vertical viewing of electron-cyclotron radiation in Text-U; measurement of temperature fluctuations from electron-cyclotron emission; a varying cross section magnetic coil diagnostic used in digital feedback control of plasma position in Text-Upgrade; high-sensitivity, high resolution measurements of radiated power on Text-U; wave launching as a diagnostic tool to investigate plasma turbulence; edge parameters from an energy analyzer and particle transport on Text-U; initial results from a charge exchange q-Diagnostic on Text-U; a method for neutral spectra analysis taking ripple-trapped particle losses into account; application of a three sample volume S(k,ω ) estimate to optical measurements of turbulence on Text; initial operation of the 2D Firsis on Text-Upgrade; horizontal-view interferometer on Text-Upgrade; plasma potential measurements on Text-Upgrade with A 2 MeV heavy ion beam; fluctuation measurements using the 2 MeV heavy ion beam probe on Text-U; the time domain triple probe method; a phase contrast imaging system for Text-U; and development of rugged corner cube detectors for the Text-U-Fir interferometer. These papers have been placed on the database elsewhere

Temperature effect on protection diode for plasma-process induced charging damage

NARCIS (Netherlands)

Wang, Zhichun; Scarpa, A.; Smits, Sander M.; Kuper, F.G.; Salm, Cora

2002-01-01

In this paper, the leakage current of different drain-well diodes for plasma-charging protection has been simulated at high temperature. The simulation shows that the high ambient temperature, especially during plasma deposition process, enormously enhances the efficacy of the protection diodes in

Temporal evolutions of electron temperature and density of turbulently-heated tokamak plasmas in TRIAM-1

Energy Technology Data Exchange (ETDEWEB)

Hiraki, N; Nakamura, K; Nakamura, Y; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-04-01

The temporal evolution of the electron temperature and density are measured in a turbulent heating experiment in TRIAM-1. Skin-like profiles of the electron temperature and density are clearly observed. The anomality in the electrical resistivity of the plasma in this skin-layer is estimated, and the plasma heating in this skin-layer is regarded as being due to anomalous joule heating arising from this anomalous resistivity. The ratio of drift velocity to electron thermal velocity in the layer is also calculated, and it is shown that the conditions needed to make the current-driven ion-acoustic instability triggerable are satisfied.

Thermal history sensors for non-destructive temperature measurements in harsh environments

Energy Technology Data Exchange (ETDEWEB)

Pilgrim, C. C. [Mechanical Engineering, Imperial College London, London, SW7 2AZ, UK and Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom); Heyes, A. L. [Energy Technology and Innovation Initiative, University of Leeds, Leeds, LS2 9JT (United Kingdom); Feist, J. P. [Sensor Coating Systems, Imperial Incubator, Bessemer Building, Level 1 and 2, Imperial College London, London SW7 2AZ (United Kingdom)

2014-02-18

The operating temperature is a critical physical parameter in many engineering applications, however, can be very challenging to measure in certain environments, particularly when access is limited or on rotating components. A new quantitative non-destructive temperature measurement technique has been proposed which relies on thermally induced permanent changes in ceramic phosphors. This technique has several distinct advantages over current methods for many different applications. The robust ceramic material stores the temperature information allowing long term thermal exposures in harsh environment to be measured at a convenient time. Additionally, rare earth dopants make the ceramic phosphorescent so that the temperature information can be interpreted by automated interrogation of the phosphorescent light. This technique has been demonstrated by application of YAG doped with dysprosium and europium as coatings through the air-plasma spray process. Either material can be used to measure temperature over a wide range, namely between 300°C and 900°C. Furthermore, results show that the material records the peak exposure temperature and prolonged exposure at lower temperatures would have no effect on the temperature measurement. This indicates that these materials could be used to measure peak operating temperatures in long-term testing.

Fly ash particles spheroidization using low temperature plasma energy

OpenAIRE

Shekhovtsov, V. V.; Volokitin, O. G.; Vitske, Rudolf Evaldovich; Kondratyuk, Alexey Alekseevich

2016-01-01

The paper presents the investigations on producing spherical particles 65-110 [mu]m in size using the energy of low temperature plasma (LTP). These particles are based on flow ash produced by the thermal power plant in Seversk, Tomsk region, Russia. The obtained spherical particles have no defects and are characterized by a smooth exterior surface. The test bench is designed to produce these particles. With due regard for plasma temperature field distribution, it is shown that the transition ...

A special cell morphology of saccharomyces cerevisiae induced by low-temperature plasma

International Nuclear Information System (INIS)

Ling Dajun; Cao Jinxiang

2003-01-01

A special cell morphology, cavity-like cells, was found in posterities of Saccharomyces cerevisiae treated by low-temperature air plasma with different powers. The feature of the special morphology indicates that the cavity-like cells may be formed by cellular mutation effect induced by the plasma, instead of direct cellular damage by the plasma. The results suggest that the cellular mutation effect of the low-temperature plasma is a complex process

Plasma Profile Measurements for Laser Fusion Research with the Nike KrF Laser

Science.gov (United States)

Oh, Jaechul; Weaver, J. L.; Serlin, V.; Obenschain, S. P.

2015-11-01

The grid image refractometer of the Nike laser facility (Nike-GIR) has demonstrated the capability of simultaneously measuring electron density (ne) and temperature (Te) profiles of coronal plasma. For laser plasma instability (LPI) research, the first Nike-GIR experiment successfully measured the plasma profiles in density regions up to ne ~ 4 ×1021 cm-3 (22% of the critical density for 248 nm light of Nike) using an ultraviolet probe laser (λp = 263 nm). The probe laser has been recently replaced with a shorter wavelength laser (λp = 213 nm, a 5th harmonic of the Nd:YAG laser) to diagnose a higher density region. The Nike-GIR system is being further extended to measure plasma profiles in the on-going experiment using 135°-separated Nike beam arrays for the cross-beam energy transfer (CBET) studies. We present an overview of the extended Nike-GIR arrangements and a new numerical algorithm to extract self-consistant plasma profiles with the measured quantities. Work supported by DoE/NNSA.

Plasma fluctuation measurements in tokamaks using beam-plasma interactions

International Nuclear Information System (INIS)

Fonck, R.J.; Duperrex, P.A.; Paul, S.F.

1990-01-01

High-frequency observations of light emitted from the interactions between plasma ions and injected neutral beam atoms allow the measurement of moderate-wavelength fluctuations in plasma and impurity ion densities. To detect turbulence in the local plasma ion density, the collisionally excited fluorescence from a neutral beam is measured either separately at several spatial points or with a multichannel imaging detector. Similarly, the role of impurity ion density fluctuations is measured using charge exchange recombination excited transitions emitted by the ion species of interest. This technique can access the relatively unexplored region of long-wavelength plasma turbulence with k perpendicular ρ i much-lt 1, and hence complements measurements from scattering experiments. Optimization of neutral beam geometry and optical sightlines can result in very good localization and resolution (Δx≤1 cm) in the hot plasma core region. The detectable fluctuation level is determined by photon statistics, atomic excitation processes, and beam stability, but can be as low as 0.2% in a 100 kHz bandwidth over the 0--1 MHz frequency range. The choices of beam species (e.g., H 0 , He 0 , etc.), observed transition (e.g., H α , L α , He I singlet or triplet transitions, C VI Δn=1, etc.) are dictated by experiment-specific factors such as optical access, flexibility of beam operation, plasma conditions, and detailed experimental goals. Initial tests on the PBX-M tokamak using the H α emissions from a heating neutral beam show low-frequency turbulence in the edge plasma region

Time and space-correlated plasma potential measurements in the near field of a coaxial Hall plasma discharge

International Nuclear Information System (INIS)

Smith, A. W.; Cappelli, M. A.

2009-01-01

Space- and time-correlated measurements of floating and plasma potential are made in the near field, external flow cathode region of a coaxial Hall plasma discharge using an emissive probe synchronized to quasicoherent fluctuations in discharge current. The luminous axial feature frequently observed in the near field of operating plasma accelerators is found to be concomitant with a spike in the plasma potential (and electron temperature). The structure of the plasma potential allows for multiple avenues for back-streaming ions to accelerate toward the discharge front pole and may pull some classes of ions toward the central axis. The fluctuations in plasma properties exhibit a complex structure at frequencies on the order of the so-called 'breathing mode' ionization instability often seen in these types of discharges. Most notably, the plasma potential appears to fluctuate in a helical fashion, resembling tilted drift waves rotating about the central axis. A simple analysis of these waves draws attention to the possible role that they may play in driving anomalous cross-field electron transport in the near field region.

Emission spectroscopy of highly ionized high-temperature plasma jets

Energy Technology Data Exchange (ETDEWEB)

Belevtsev, A A; Chinnov, V F; Isakaev, E Kh [Associated Institute for High Temperatures, Russian Academy of Sciences Izhorskaya 13/19, Moscow, 125412 (Russian Federation)

2006-08-01

This paper deals with advanced studies on the optical emission spectroscopy of atmospheric pressure highly ionized high-temperature argon and nitrogen plasma jets generated by a powerful arc plasmatron. The emission spectra are taken in the 200-1000 nm range with a spectral resolution of {approx}0.01-0.02 nm. The exposure times are 6 x 10{sup -6}-2 x 10{sup -2} s, the spatial resolution is 0.02-0.03 mm. The recorded jet spectra are abundant in spectral lines originating from different ionization stages. In nitrogen plasmas, tens of vibronic bands are also observed. To interpret and process these spectra such that plasma characteristics can be derived, a purpose-developed automated processing system is applied. The use of a CCD camera at the spectrograph output allows a simultaneous recording of the spectral and chord intensity distributions of spectral lines, which can yet belong to the overlapped spectra of the first and second orders of interference. The modern optical diagnostic means and methods used permit the determination of spatial distributions of electron number densities and temperatures and evaluation of rotational temperatures. The radial profiles of the irradiating plasma components can also be obtained. Special attention is given to the method of deriving rotational temperatures using vibronic bands with an incompletely identified rotational structure.

A measurement of the local ion temperature gradient in the PLT tokamak

International Nuclear Information System (INIS)

Lovberg, J.A.; Strachan, J.D.; Princeton Univ., NJ

1989-12-01

Local ion temperature gradients were measured at two radial positions in the PLT tokamak by counting escaping d(d,p)t protons on orbits at closely spaced intervals. A single surface barrier detector was used to make each gradient measurement, eliminating relative calibration uncertainties. The ion thermal diffusivities inferred through ion energy balance with the measured temperature gradients are within a factor of two of Chang-Hinton neoclassical values for the 3 He-minority ICRH plasmas. 12 refs., 8 figs

Plasma flow reactor for steady state monitoring of physical and chemical processes at high temperatures.

Science.gov (United States)

Koroglu, Batikan; Mehl, Marco; Armstrong, Michael R; Crowhurst, Jonathan C; Weisz, David G; Zaug, Joseph M; Dai, Zurong; Radousky, Harry B; Chernov, Alex; Ramon, Erick; Stavrou, Elissaios; Knight, Kim; Fabris, Andrea L; Cappelli, Mark A; Rose, Timothy P

2017-09-01

We present the development of a steady state plasma flow reactor to investigate gas phase physical and chemical processes that occur at high temperature (1000 flow injector). We have modeled the system using computational fluid dynamics simulations that are bounded by measured temperatures. In situ line-of-sight optical emission and absorption spectroscopy have been used to determine the structures and concentrations of molecules formed during rapid cooling of reactants after they pass through the plasma. Emission spectroscopy also enables us to determine the temperatures at which these dynamic processes occur. A sample collection probe inserted from the open end of the reactor is used to collect condensed materials and analyze them ex situ using electron microscopy. The preliminary results of two separate investigations involving the condensation of metal oxides and chemical kinetics of high-temperature gas reactions are discussed.

Rotating structures in low temperature magnetized plasmas - Insight from particle simulations

Directory of Open Access Journals (Sweden)

Jean-Pierre eBoeuf

2014-12-01

Full Text Available The EXB configuration of various low temperature plasma devices is often responsible for the formation of rotating structures and instabilities leading to anomalous electron transport across the magnetic field. In these devices, electrons are strongly magnetized while ions are weakly or not magnetized and this leads to specific physical phenomena that are not present in fusion plasmas where both electrons and ions are strongly magnetized. In this paper we describe basic phenomena involving rotating plasma structures in simple configurations of low temperature EXB plasma devices on the basis of PIC-MCC (Particle-In-Cell Monte Carlo Collisions simulations. We focus on three examples: rotating electron vortices and rotating spokes in cylindrical magnetrons, and azimuthal electron-cyclotron drift instability in Hall thrusters. The simulations are not intended to give definite answers to the many physics issues related to low temperature EXB plasma devices but are used to illustrate and discuss some of the basic questions that need further studies.

Fluctuations of the electron temperature measured by intensity interferometry on the W7-AS stellarator

International Nuclear Information System (INIS)

Sattler, S.

1993-12-01

Fluctuations of the electron temperature can cause a significant amount of the anomalous electron heat conductivity observed on fusion plasmas, even with relative amplitudes below one per cent. None of the standard diagnostics utilized for measuring the electron temperature in the confinement region of fusion plasmas is provided with sufficient spatial and temporal resolution and the sensitivity for small fluctuation amplitudes. In this work a new diagnostic for the measurement of electron temperature fluctuations in the confinement region of fusion plasmas was developed, built up, tested and successfully applied on the W7-AS Stellarator. Transport relevant fluctuations of the electron temperature can in principle be measured by radiometry of the electron cyclotron emission (ECE), but they might be buried completely in natural fluctuations of the ECE due to the thermal nature of this radiation. Fluctuations with relative amplitudes below one per cent can be measured with a temporal resolution in the μs-range and a spatial resolution of a few cm only with the help of correlation techniques. The intensity interferometry method, developed for radio astronomy, was applied here: two independent but identical radiometers are viewing the same emitting volume along crossed lines of sight. If the angle between the sightlines is chosen above a limiting value, which is determined by the spatial coherence properties of thermal radiation, the thermal noise is uncorrelated while the temperature fluctuations remain correlated. With the help of this technique relative amplitudes below 0.1% are accessible to measurement. (orig.)

The ionization length in plasmas with finite temperature ion sources

Science.gov (United States)

Jelić, N.; Kos, L.; Tskhakaya, D. D.; Duhovnik, J.

2009-12-01

The ionization length is an important quantity which up to now has been precisely determined only in plasmas which assume that the ions are born at rest, i.e., in discharges known as "cold ion-source" plasmas. Presented here are the results of our calculations of the ionization lengths in plasmas with an arbitrary ion source temperature. Harrison and Thompson (H&T) [Proc. Phys. Soc. 74, 145 (1959)] found the values of this quantity for the cases of several ion strength potential profiles in the well-known Tonks-Langmuir [Phys. Rev. 34, 876 (1929)] discharge, which is characterized by "cold" ion temperature. This scenario is also known as the "singular" ion-source discharge. The H&T analytic result covers cases of ion sources proportional to exp(βΦ) with Φ the normalized plasma potential and β =0,1,2 values, which correspond to particular physical scenarios. Many years following H&T's work, Bissell and Johnson (B&J) [Phys. Fluids 30, 779 (1987)] developed a model with the so-called "warm" ion-source temperature, i.e., "regular" ion source, under B&J's particular assumption that the ionization strength is proportional to the local electron density. However, it appears that B&J were not interested in determining the ionization length at all. The importance of this quantity to theoretical modeling was recognized by Riemann, who recently answered all the questions of the most advanced up-to-date plasma-sheath boundary theory with cold ions [K.-U. Riemann, Phys. Plasmas 13, 063508 (2006)] but still without the stiff warm ion-source case solution, which is highly resistant to solution via any available analytic method. The present article is an extension of H&T's results obtained for a single point only with ion source temperature Tn=0 to arbitrary finite ion source temperatures. The approach applied in this work is based on the method recently developed by Kos et al. [Phys. Plasmas 16, 093503 (2009)].

The plasma-wall interaction region: a key low temperature plasma for controlled fusion

International Nuclear Information System (INIS)

Counsell, G F

2002-01-01

The plasma-wall interaction region of a fusion device provides the interface between the hot core plasma and the material surfaces. To obtain acceptably low levels of erosion from these surfaces requires most of the power leaving the core to be radiated. This is accomplished in existing devices by encouraging plasma detachment, in which the hot plasma arriving in the region is cooled by volume recombination and ion-neutral momentum transfer with a dense population of neutrals recycled from the surface. The result is a low temperature (1 eV e e >10 19 m -3 ) but weakly ionized (n 0 >10 20 m -3 , n e /n 0 <0.1) plasma found nowhere else in the fusion environment. This plasma provides many of the conditions found in industrial plasmas exploiting plasma chemistry and the presence of carbon in the region (in the form of carbon-fibre composite used in the plasma facing materials) can result in the formation of deposited hydrocarbon films. The plasma-wall interaction region is therefore among the most difficult in fusion to model, requiring an understanding of atomic, molecular and surface physics issues

Ion temperature measurements of H-, D- and He-plasmas in the TCA tokamak by collective Thomson scattering of D2O laser radiation

International Nuclear Information System (INIS)

Behn, R.; Dicken, D.; Hackmann, J.; Salito, S.A.; Siegrist, M.R.

1989-01-01

Development of collective Thomson scattering as a method to measure the ion temperature of a tokamak plasma has been successful and encouraging results have been obtained during experiments on TCA in H-, D- and He-plasmas. Using a laser source in the far-infrared spectral region allows scattering angles close to 90 o , which results in excellent spatial resolution. The system installed on the TCA tokamak comprises an optically pumped D 2 O laser emitting 0.5 J in a 1.4 μs pulse on its Raman transition at 385μm. A heterodyne receiver with a Schottky barrier diode mixer has been chosen to detect the scattered radiation and analyze its spectral distribution in 12 channels of 80 MHz. Recent improvements of the mixer and 1st IF-amplifier yielded a system NEP of 2.2·10 -19 W/Hz. As a consequence we have obtained results which allow for the first time to evaluate the ion temperature T i in a single laser shot. (author) 3 figs., 1 tab

Low-temperature plasma nitriding of sintered PIM 316L austenitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Mendes, Aecio Fernando; Scheuer, Cristiano Jose; Joanidis, Ioanis Labhardt; Cardoso, Rodrigo Perito; Mafra, Marcio; Klein, Aloisio Nelmo; Brunatto, Silvio Francisco, E-mail: brunatto@ufpr.br [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica. Grupo de Tecnologia de Fabricacao Assistida pro Plasma e Metalurgia do Po

2014-08-15

This work reports experimental results on sintered PIM 316L stainless steel low-temperature plasma nitriding. The effect of treatment temperature and time on process kinetics, microstructure and surface characteristics of the nitrided samples were investigated. Nitriding was carried out at temperatures of 350, 380, 410 and 440 °C , and times of 4, 8 and 16 h, using a gas mixture composed by 60% N2 + 20% H2 + 20% Ar, at a gas flow rate of 5.00 X 10{sup 6} Nm{sup 3-1}, and a pressure of 800 Pa. The treated samples were characterized by scanning electron microscopy, X-ray diffractometry and microhardness measurements. Results indicate that low-temperature plasma nitriding is a diffusion controlled process. The calculated activation energy for nitrided layer growth was 111.4 kJmol{sup -1}. Apparently precipitation-free layers were produced in this study. It was also observed that the higher the treatment temperature and time the higher is the obtained surface hardness. Hardness up to 1343 HV{sub 0.025} was verified for samples nitrided at 440 °C. Finally, the characterization of the treated surface indicates the formation of cracks, which were observed in regions adjacent to the original pores after the treatment. (author)

Low temperature plasma near a tokamak reactor limiter

International Nuclear Information System (INIS)

Braams, B.J.; Singer, C.E.

1985-01-01

Analytic and two-dimensional computational solutions for the plasma parameters near a toroidally symmetric limiter are illustrated for the projected parameters of a Tokamak Fusion Core Experiment (TFCX). The temperature near the limiter plate is below 20 eV, except when the density 10 cm inside the limiter contact is 8 x 10 13 cm -3 or less and the thermal diffusivity in the edge region is 2 x 10 4 cm 2 /s or less. Extrapolation of recent experimental data suggests that neither of these conditions is likely to be met near ignition in TFCX, so a low plasma temperature near the limiter should be considered a likely possibility

Tomographic Measurements of Temperature Fluctuations in an Air Plasma Cutting Torch

Czech Academy of Sciences Publication Activity Database

Hlína, Jan; Šonský, Jiří; Gruber, Jan

2017-01-01

Roč. 37, č. 3 (2017), s. 689-699 ISSN 0272-4324 Institutional support: RVO:61388998 Keywords : cutting arc * air plasma * tomography Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.355, year: 2016 http://link.springer.com/ article /10.1007%2Fs11090-017-9794-x

Microcantilever based disposable viscosity sensor for serum and blood plasma measurements.

Science.gov (United States)

Cakmak, Onur; Elbuken, Caglar; Ermek, Erhan; Mostafazadeh, Aref; Baris, Ibrahim; Erdem Alaca, B; Kavakli, Ibrahim Halil; Urey, Hakan

2013-10-01

This paper proposes a novel method for measuring blood plasma and serum viscosity with a microcantilever-based MEMS sensor. MEMS cantilevers are made of electroplated nickel and actuated remotely with magnetic field using an electro-coil. Real-time monitoring of cantilever resonant frequency is performed remotely using diffraction gratings fabricated at the tip of the dynamic cantilevers. Only few nanometer cantilever deflection is sufficient due to interferometric sensitivity of the readout. The resonant frequency of the cantilever is tracked with a phase lock loop (PLL) control circuit. The viscosities of liquid samples are obtained through the measurement of the cantilever's frequency change with respect to a reference measurement taken within a liquid of known viscosity. We performed measurements with glycerol solutions at different temperatures and validated the repeatability of the system by comparing with a reference commercial viscometer. Experimental results are compared with the theoretical predictions based on Sader's theory and agreed reasonably well. Afterwards viscosities of different Fetal Bovine Serum and Bovine Serum Albumin mixtures are measured both at 23°C and 37°C, body temperature. Finally the viscosities of human blood plasma samples taken from healthy donors are measured. The proposed method is capable of measuring viscosities from 0.86 cP to 3.02 cP, which covers human blood plasma viscosity range, with a resolution better than 0.04 cP. The sample volume requirement is less than 150 μl and can be reduced significantly with optimized cartridge design. Both the actuation and sensing are carried out remotely, which allows for disposable sensor cartridges. Copyright © 2013. Published by Elsevier Inc.

Two-photon LIF on the HIT-SI3 experiment: Absolute density and temperature measurements of deuterium neutrals

Energy Technology Data Exchange (ETDEWEB)

Elliott, Drew, E-mail: dbelliott@mix.wvu.edu; Siddiqui, Umair; Scime, Earl [Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26056 (United States); Sutherland, Derek; Everson, Chris; Morgan, Kyle; Hossack, Aaron; Nelson, Brian; Jarboe, Tom [Department of Aerospace Engineering, University of Washington, Seattle, Washington 98105 (United States)

2016-11-15

Two-photon laser-induced fluorescence measurements were performed on the helicity injected torus (HIT-SI3) device to determine the density and temperature of the background neutral deuterium population. Measurements were taken in 2 ms long pulsed plasmas after the inductive helicity injectors were turned off. Attempts to measure neutrals during the main phase of the plasma were unsuccessful, likely due to the density of neutrals being below the detection threshold of the diagnostic. An unexpectedly low density of atomic deuterium was measured in the afterglow; roughly 100 times lower than the theoretical prediction of 10{sup 17} m{sup −3}. The neutral temperatures measured were on the order of 1 eV. Temporally and spatially resolved neutral density and temperature data are presented.

Temperature determination from a real plasma from line self-reversal

International Nuclear Information System (INIS)

Salakhov, M.K.; Fishman, I.S.

1981-01-01

The coefficient Z = M/sub infinity/Y/sub infinity/ is determined on the basis of the actual structure of a plasma (the M/sub infinity/ and Y/sub infinity/ coefficients in Bartels's theory). The absorption and emission spectra are utilized as recorded in a transverse section of the plasma, which are used in determining the actual course of the atomic concentration and the half-width of the thin-layer line. An iterative scheme is set up for determining the temperature. A mathematical experiment has been performed and the temperature distribution has been determined in the plasma of a low-voltage pulsed discharge

Measurement of the non-thermal properties in a low-pressure spraying plasma

International Nuclear Information System (INIS)

Jung, Yong Ho; Chung, Kyu Sun

2002-01-01

The non-thermal properties of a low-pressure spraying plasma have been characterized by using optical emission spectroscopy and single probes installed in a fast scanning probe system. A two-temperature model of the electrons is introduced to explain their non-isothermal properties, which are measured using single probes. The excitation temperatures of the atomic and the ionic lines are calculated from measurements of the emission intensities of Ar (I) and Ar (II), and those temperatures can be explained by using a local thermodynamic equilibrium (LTE) or a non-local thermodynamic equilibrium (non-LTE) model. In order to deduce more reasonable values (excitation temperatures), we introduce a multi-thermodynamic equilibrium (MTE) model, which gives different temperatures, depending upon the atomic excitation states

Ideal laser-beam propagation through high-temperature ignition Hohlraum plasmas.

Science.gov (United States)

Froula, D H; Divol, L; Meezan, N B; Dixit, S; Moody, J D; Neumayer, P; Pollock, B B; Ross, J S; Glenzer, S H

2007-02-23

We demonstrate that a blue (3omega, 351 nm) laser beam with an intensity of 2 x 10(15) W cm(-2) propagates nearly within the original beam cone through a millimeter scale, T(e)=3.5 keV high density (n(e)=5 x 10(20) cm(-3)) plasma. The beam produced less than 1% total backscatter at these high temperatures and densities; the resulting transmission is greater than 90%. Scaling of the electron temperature in the plasma shows that the plasma becomes transparent for uniform electron temperatures above 3 keV. These results are consistent with linear theory thresholds for both filamentation and backscatter instabilities inferred from detailed hydrodynamic simulations. This provides a strong justification for current inertial confinement fusion designs to remain below these thresholds.

Nonlinear quantum fluid equations for a finite temperature Fermi plasma

International Nuclear Information System (INIS)

Eliasson, Bengt; Shukla, Padma K

2008-01-01

Nonlinear quantum electron fluid equations are derived, taking into account the moments of the Wigner equation and by using the Fermi-Dirac equilibrium distribution for electrons with an arbitrary temperature. A simplified formalism with the assumptions of incompressibility of the distribution function is used to close the moments in velocity space. The nonlinear quantum diffraction effects into the fluid equations are incorporated. In the high-temperature limit, we retain the nonlinear fluid equations for a dense hot plasma and in the low-temperature limit, we retain the correct fluid equations for a fully degenerate plasma

Electron temperature measurement of tungsten inert gas arcs

International Nuclear Information System (INIS)

Tanaka, Manabu; Tashiro, Shinichi

2008-01-01

In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

PWFA plasma source - interferometric diagnostics for Li vapor density measurements

International Nuclear Information System (INIS)

Sivakumaran, V.; Mohandas, K.K.; Singh, Sneha; Ravi Kumar, A.V.

2015-01-01

A prototype (40 cm long) plasma source based on Li heat pipe oven has been developed for the Plasma Wakefield Acceleration (PWFA) experiments at IPR (IPR), Gujarat as a part of the ongoing Accelerator Programme. Li vapor in the oven is produced by heating solid Li in helium buffer gas. A uniform column of Li plasma is generated by UV photo ionization (193 nm) of the Li vapor in the heat pipe oven. In these experiments, an accurate measurement of Li vapor density is important as it has got a direct consequence on the plasma electron density. In the present experiment, the vapor density is measured optically by using Hook method (spectrally resolved white light interferometry). The hook like structure formed near the vicinity of the Li 670.8 nm resonance line was recorded with a white light Mach Zehnder interferometer crossed with an imaging spectrograph to estimate the Li vapor density. The vapor density measurements have been carried out as a function of external oven temperature and the He buffer gas pressure. This technique has the advantage of being insensitive to line broadening and line shape, and its high dynamic range even with optically thick absorption line. Here, we present the line integrated Lithium vapor density measurement using Hook method and also compare the same with other optical diagnostic techniques (White light absorption and UV absorption) for Li vapor density measurements. (author)

Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma.

Science.gov (United States)

Schäfer, J; Foest, R; Reuter, S; Kewitz, T; Šperka, J; Weltmann, K-D

2012-10-01

The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 ± 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 ± 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

Laser schlieren deflectometry for temperature analysis of filamentary non-thermal atmospheric pressure plasma

Energy Technology Data Exchange (ETDEWEB)

Schaefer, J.; Foest, R.; Reuter, S.; Weltmann, K.-D. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Kewitz, T. [Institute of Experimental and Applied Physics, University Kiel, 24098 Kiel (Germany); Sperka, J. [Department of Physical Electronics, Masaryk University, 61137 Brno (Czech Republic)

2012-10-15

The heat convection generated by micro filaments of a self-organized non-thermal atmospheric pressure plasma jet in Ar is characterized by employing laser schlieren deflectometry (LSD). It is demonstrated as a proof of principle, that the spatial and temporal changes of the refractive index n in the optical beam path related to the neutral gas temperature of the plasma jet can be monitored and evaluated simultaneously. The refraction of a laser beam in a high gradient field of n(r) with cylindrical symmetry is given for a general real refraction index profile. However, the usually applied Abel approach represents an ill-posed problem and in particular for this plasma configuration. A simple analytical model is proposed in order to minimize the statistical error. Based on that, the temperature profile, specifically the absolute temperature in the filament core, the FWHM, and the frequencies of the collective filament dynamics are obtained for non-stationary conditions. For a gas temperature of 700 K inside the filament, the presented model predicts maximum deflection angles of the laser beam of 0.3 mrad which is in accordance to the experimental results obtained with LSD. Furthermore, the experimentally obtained FWHM of the temperature profile produced by the filament at the end of capillary is (1.5 {+-} 0.2) mm, which is about 10 times wider than the visual radius of the filament. The obtained maximum temperature in the effluent is (450 {+-} 30) K and is in consistence with results of other techniques. The study demonstrates that LSD represents a useful low-cost method for monitoring the spatiotemporal behaviour of microdischarges and allows to uncover their dynamic characteristics, e.g., the temperature profile even for challenging diagnostic conditions such as moving thin discharge filaments. The method is not restricted to the miniaturized and self-organized plasma studied here. Instead, it can be readily applied to other configurations that produce measurable

Divertor, thermonuclear device and method of neutralizing high temperature plasma

International Nuclear Information System (INIS)

Ikegami, Hideo.

1995-01-01

The thermonuclear device comprises a thermonuclear reactor for taking place fusion reactions to emit fusion plasmas, and a divertor made of a hydrogen occluding material, and the divertor is disposed at a position being in contact with the fusion plasmas after nuclear fusion reaction. The divertor is heated by fusion plasmas after nuclear fusion reaction, and hydrogen is released from the hydrogen occluding material as a constituent material. A gas blanket is formed by the released hydrogen to cool and neutralize the supplied high temperature nuclear fusion plasmas. This prevents the high temperature plasmas from hitting against the divertor, elimination of the divertor by melting and evaporation, and solve a problem of processing a divertor activated by neutrons. In addition, it is possible to utilize hydrogen isotopes of fuels effectively and remove unnecessary helium. Inflow of impurities from out of the system can also be prevented. (N.H.)

Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

International Nuclear Information System (INIS)

Xiao-Yuan, Xu; Jun, Wang; Yi, Yu; Yi-Zhi, Wen; Chang-Xuan, Yu; Wan-Dong, Liu; Bao-Nian, Wan; Xiang, Gao; Luhmann, N. C.; Domier, C. W.; Wang, Jian; Xia, Z. G.; Shen, Zuowei

2009-01-01

The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number k-bar θ is calculated to be about 1.58 cm −1 , or k-bar θρ s thickapprox 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation. (fluids, plasmas and electric discharges)

Plasma temperature during methylene blue/light treatment influences virus inactivation capacity and product quality.

Science.gov (United States)

Gravemann, U; Handke, W; Sumian, C; Alvarez, I; Reichenberg, S; Müller, T H; Seltsam, A

2018-02-27

Photodynamic treatment using methylene blue (MB) and visible light is in routine use for pathogen inactivation of human plasma in different countries. Ambient and product temperature conditions for human plasma during production may vary between production sites. The influence of different temperature conditions on virus inactivation capacity and plasma quality of the THERAFLEX MB-Plasma procedure was investigated in this study. Plasma units equilibrated to 5 ± 2°C, room temperature (22 ± 2°C) or 30 ± 2°C were treated with MB/light and comparatively assessed for the inactivation capacity for three different viruses, concentrations of MB and its photoproducts, activity of various plasma coagulation factors and clotting time. Reduced solubility of the MB pill was observed at 5 ± 2°C. Photocatalytic degradation of MB increased with increasing temperature, and the greatest formation of photoproducts (mainly azure B) occurred at 30 ± 2°C. Inactivation of suid herpesvirus, bovine viral diarrhoea virus and vesicular stomatitis virus was significantly lower at 5 ± 2°C than at higher temperatures. MB/light treatment affected clotting times and the activity of almost all investigated plasma proteins. Factor VIII (-17·7 ± 8·3%, 22 ± 2°C) and fibrinogen (-14·4 ± 16·4%, 22 ± 2°C) showed the highest decreases in activity. Increasing plasma temperatures resulted in greater changes in clotting time and higher losses of plasma coagulation factor activity. Temperature conditions for THERAFLEX MB-Plasma treatment must be carefully controlled to assure uniform quality of pathogen-reduced plasma in routine production. Inactivation of cooled plasma is not recommended. © 2018 International Society of Blood Transfusion.

Pedestal Temperature Model for Type III ELMy H-mode Plasma

International Nuclear Information System (INIS)

Buangam, W.; Suwanna, S.; Onjun, T.; Poolyarat, N.; Picha, R.; Singhsomroje, W.

2009-07-01

Full text: It is widely known that the improved performance of H-mode plasma results mainly from a formation of the pedestal, which is a narrow region of strong pressure gradient near the edge of plasma. A predictive capability for the conditions at the top of the pedestal is important, especially for predictive simulations of future experiments. New models for predicting the temperature values at the top of the pedestal for type III ELMy H-mode plasma are developed by using two different approaches: a theory-based approaches and an empirical approach. For a theory-based approach, a model is developed based on the calculation of thermal energy in the pedestal region and on accepted scaling laws of energy confinement time. For an empirical model, a scaling law for pedestal temperature in terms of plasma controlled parameters, such as plasma current, magnetic field, heating power, is deduced from experimental data. Predictions from these models are compared with experimental data from the Pedestal International Database. Statistical quantities, such as Root-Mean Square Error (RMSE) and offset values, are computed to quantify the predictive capability of the models. It is found that the theory-based model predicts the pedestal temperature values moderately well yielding RMSE between 30% and 40%. The IPB98(y,3) scaling law yields with best agreement with RMSE of 30.4%. The empirical model predicts the pedestal temperature value with better agreement, yield RMSE of 25.9%

Kr II laser-induced fluorescence for measuring plasma acceleration.

Science.gov (United States)

Hargus, W A; Azarnia, G M; Nakles, M R

2012-10-01

We present the application of laser-induced fluorescence of singly ionized krypton as a diagnostic technique for quantifying the electrostatic acceleration within the discharge of a laboratory cross-field plasma accelerator also known as a Hall effect thruster, which has heritage as spacecraft propulsion. The 728.98 nm Kr II transition from the metastable 5d(4)D(7/2) to the 5p(4)P(5/2)(∘) state was used for the measurement of laser-induced fluorescence within the plasma discharge. From these measurements, it is possible to measure velocity as krypton ions are accelerated from near rest to approximately 21 km/s (190 eV). Ion temperature and the ion velocity distributions may also be extracted from the fluorescence data since available hyperfine splitting data allow for the Kr II 5d(4)D(7/2)-5p(4)P(5/2)(∘) transition lineshape to be modeled. From the analysis, the fluorescence lineshape appears to be a reasonable estimate for the relatively broad ion velocity distributions. However, due to an apparent overlap of the ion creation and acceleration regions within the discharge, the distributed velocity distributions increase ion temperature determination uncertainty significantly. Using the most probable ion velocity as a representative, or characteristic, measure of the ion acceleration, overall propellant energy deposition, and effective electric fields may be calculated. With this diagnostic technique, it is possible to nonintrusively characterize the ion acceleration both within the discharge and in the plume.

Hematocrit and plasma osmolality values of young-of-year shortnose sturgeon following acute exposures to combinations of salinity and temperature

Science.gov (United States)

Ziegeweid, J.R.; Black, M.C.

2010-01-01

Little is known about the physiological capabilities of young-of-year (YOY) shortnose sturgeon. In this study, plasma osmolality and hematocrit values were measured for YOY shortnose sturgeon following 48-h exposures to 12 different combinations of salinity and temperature. Hematocrit levels varied significantly with temperature and age, and plasma osmolalities varied significantly with salinity and age. Plasma osmolality and hematocrit values were similar to previously published values for other sturgeons of similar age and size in similar treatment conditions. ?? 2010 Springer Science+Business Media B.V.

High temperature electrons exhausted from rf plasma sources along a magnetic nozzle

Science.gov (United States)

Takahashi, Kazunori; Akahoshi, Hikaru; Charles, Christine; Boswell, Rod W.; Ando, Akira

2017-08-01

Two dimensional profiles of electron temperature are measured inside and downstream of a radiofrequency plasma thruster source having a magnetic nozzle and being immersed in vacuum. The temperature is estimated from the slope of the fully swept I-V characteristics of a Langmuir probe acquired at each spatial position and with the assumption of a Maxwellian distribution. The results show that the peripheral high temperature electrons in the magnetic nozzle originate from the upstream antenna location and are transported along the "connecting" magnetic field lines. Two-dimensional measurements of electron energy probability functions are also carried out in a second simplified laboratory device consisting of the source contiguously connected to the diffusion chamber: again the high temperature electrons are detected along the magnetic field lines intersecting the wall at the antenna location, even when the antenna location is shifted along the main axis. These results demonstrate that the peripheral energetic electrons in the magnetic nozzle mirror those created in the source tube.

Spectroscopic measurements of plasma emission light for plasma-based acceleration experiments

International Nuclear Information System (INIS)

Filippi, F.; Mostacci, A.; Palumbo, L.; Anania, M.P.; Biagioni, A.; Chiadroni, E.; Ferrario, M.; Cianchi, A.; Zigler, A.

2016-01-01

Advanced particle accelerators are based on the excitation of large amplitude plasma waves driven by either electron or laser beams. Future experiments scheduled at the SPARC-LAB test facility aim to demonstrate the acceleration of high brightness electron beams through the so-called resonant Plasma Wakefield Acceleration scheme in which a train of electron bunches (drivers) resonantly excites wakefields into a preformed hydrogen plasma; the last bunch (witness) injected at the proper accelerating phase gains energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The measurements of plasma density of the order of 10 16 –10 17  cm −3 can be performed with spectroscopic measurements of the plasma-emitted light. The measured density distribution for hydrogen filled capillary discharge with both Balmer alpha and Balmer beta lines and shot-to-shot variation are here reported.

Spectroscopic measurements of plasma emission light for plasma-based acceleration experiments

Science.gov (United States)

Filippi, F.; Anania, M. P.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Ferrario, M.; Mostacci, A.; Palumbo, L.; Zigler, A.

2016-09-01

Advanced particle accelerators are based on the excitation of large amplitude plasma waves driven by either electron or laser beams. Future experiments scheduled at the SPARC_LAB test facility aim to demonstrate the acceleration of high brightness electron beams through the so-called resonant Plasma Wakefield Acceleration scheme in which a train of electron bunches (drivers) resonantly excites wakefields into a preformed hydrogen plasma; the last bunch (witness) injected at the proper accelerating phase gains energy from the wake. The quality of the accelerated beam depends strongly on plasma density and its distribution along the acceleration length. The measurements of plasma density of the order of 1016-1017 cm-3 can be performed with spectroscopic measurements of the plasma-emitted light. The measured density distribution for hydrogen filled capillary discharge with both Balmer alpha and Balmer beta lines and shot-to-shot variation are here reported.

Schlieren technique applied to the arc temperature measurement in a high energy density cutting torch

International Nuclear Information System (INIS)

Prevosto, L.; Mancinelli, B.; Artana, G.; Kelly, H.

2010-01-01

Plasma temperature and radial density profiles of the plasma species in a high energy density cutting arc have been obtained by using a quantitative schlieren technique. A Z-type two-mirror schlieren system was used in this research. Due to its great sensibility such technique allows measuring plasma composition and temperature from the arc axis to the surrounding medium by processing the gray-level contrast values of digital schlieren images recorded at the observation plane for a given position of a transverse knife located at the exit focal plane of the system. The technique has provided a good visualization of the plasma flow emerging from the nozzle and its interactions with the surrounding medium and the anode. The obtained temperature values are in good agreement with those values previously obtained by the authors on the same torch using Langmuir probes.

Thomson scattering measurements of ion interpenetration in cylindrically converging, supersonic magnetized plasma flows

Science.gov (United States)

Swadling, George

2015-11-01

Ion interpenetration driven by high velocity plasma collisions is an important phenomenon in high energy density environments such as the interiors of ICF vacuum hohlraums and fast z-pinches. The presence of magnetic fields frozen into these colliding flows further complicates the interaction dynamics. This talk focuses on an experimental investigation of ion interpenetration in collisions between cylindrically convergent, supersonic, magnetized flows (M ~10, Vflow ~ 100km/s, ni ~ 1017cm-3) . The flows used in this study were plasma ablation streams produced by tungsten wire array z-pinches, driven by the 1.4MA, 240ns Magpie facility at Imperial College, and diagnosed using a combination of optical Thomson scattering, Faraday rotation and interferometry. Optical Thomson scattering (TS) provides time-resolved measurements of local flow velocity and plasma temperature across multiple (7 to 14) spatial positions. TS spectra are recorded simultaneously from multiple directions with respect to the probing beam, resulting in separate measurements of the rates of transverse diffusion and slowing-down of the ion velocity distribution. The measurements demonstrate flow interpenetration through the array axis at early time, and also show an axial deflection of the ions towards the anode. This deflection is induced by a toroidal magnetic field (~ 10T), frozen into the plasma that accumulates near the axis. Measurements obtained later in time show a change in the dynamics of the stream interactions, transitioning towards a collisional, shock-like interaction of the streams, and rapid radial collapse of the magnetized plasma column. The quantitative nature of the spatial profiles of the density, flow velocities and ion temperatures measured in these experiments will allow detailed verification of MHD and PIC codes used by the HEDP community. Work Supported by EPSRC (Grant No. EP/G001324/1), DOE (Cooperative Agreement Nos. DE-F03-02NA00057 & DE-SC-0001063) & Sandia National

Soft x-ray continuum radiation transmitted through metallic filters: An analytical approach to fast electron temperature measurements

International Nuclear Information System (INIS)

Delgado-Aparicio, L.; Hill, K.; Bitter, M.; Tritz, K.; Kramer, T.; Stutman, D.; Finkenthal, M.

2010-01-01

A new set of analytic formulas describes the transmission of soft x-ray continuum radiation through a metallic foil for its application to fast electron temperature measurements in fusion plasmas. This novel approach shows good agreement with numerical calculations over a wide range of plasma temperatures in contrast with the solutions obtained when using a transmission approximated by a single-Heaviside function [S. von Goeler et al., Rev. Sci. Instrum. 70, 599 (1999)]. The new analytic formulas can improve the interpretation of the experimental results and thus contribute in obtaining fast temperature measurements in between intermittent Thomson scattering data.

High-resolution spectroscopy diagnostics for measuring impurity ion temperature and velocity on the COMPASS tokamak

Energy Technology Data Exchange (ETDEWEB)

Weinzettl, Vladimir, E-mail: vwei@ipp.cas.cz [Institute of Plasma Physics ASCR, Prague (Czech Republic); Shukla, Gaurav [Institute of Plasma Physics ASCR, Prague (Czech Republic); Department of Applied Physics, Ghent University, Ghent (Belgium); Faculty of Mathematics and Physics, Charles University in Prague, Prague (Czech Republic); Ghosh, Joydeep [Institute for Plasma Research, Bhat, Gandhinagar (India); Melich, Radek; Panek, Radomir [Institute of Plasma Physics ASCR, Prague (Czech Republic); Tomes, Matej; Imrisek, Martin; Naydenkova, Diana [Institute of Plasma Physics ASCR, Prague (Czech Republic); Faculty of Mathematics and Physics, Charles University in Prague, Prague (Czech Republic); Varju, Josef [Institute of Plasma Physics ASCR, Prague (Czech Republic); Pereira, Tiago [Instituto de Plasmas e Fusão Nuclear, Lisboa (Portugal); Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Gomes, Rui [Instituto de Plasmas e Fusão Nuclear, Lisboa (Portugal); Abramovic, Ivana; Jaspers, Roger [Eindhoven University of Technology, Eindhoven (Netherlands); Pisarik, Michael [SQS Vlaknova optika a.s., Nova Paka (Czech Republic); Department of Electromagnetic Field, Faculty of Electrical Engineering, Czech Technical University in Prague (Czech Republic); Odstrcil, Tomas [Max-Planck-Institut fur Plasmaphysik, Garching (Germany); Van Oost, Guido [Department of Applied Physics, Ghent University, Ghent (Belgium)

2015-10-15

Highlights: • We built a new diagnostic of poloidal plasma rotation on the COMPASS tokamak. • Improvements in throughput via toroidal integration and fiber optimizations shown. • Poloidal rotation and ion temperature measured in L- and H-mode and during RMP. • Design and parameters of a new CXRS diagnostic for COMPASS are introduced. - Abstract: High-resolution spectroscopy is a powerful tool for the measurement of plasma rotation as well as ion temperature using the Doppler shift of the emitted spectral lines and their Doppler broadening, respectively. Both passive and active diagnostic variants for the COMPASS tokamak are introduced. The passive diagnostic focused on the C III lines at about 465 nm is utilized for the observation of the poloidal plasma rotation. The current set-up of the measuring system is described, including the intended high-throughput optics upgrade. Different options to increase the fiber collection area are mentioned, including a flower-like fiber bundle, and the use of micro-lenses or tapered fibers. Recent measurements of poloidal plasma rotation of the order of 0–6 km/s are shown. The design of the new active diagnostic using a deuterium heating beam and based on charge exchange recombination spectroscopy (C VI line at 529 nm) is introduced. The tool will provide both space (0.5–5 cm) and time (10 ms) resolved toroidal plasma rotation and ion temperature profiles. The results of the Simulation of Spectra code used to examine the feasibility of charge exchange measurements on COMPASS are shown and connected with a selection of the spectrometer coupled with the CCD camera.

High-resolution spectroscopy diagnostics for measuring impurity ion temperature and velocity on the COMPASS tokamak

International Nuclear Information System (INIS)

Weinzettl, Vladimir; Shukla, Gaurav; Ghosh, Joydeep; Melich, Radek; Panek, Radomir; Tomes, Matej; Imrisek, Martin; Naydenkova, Diana; Varju, Josef; Pereira, Tiago; Gomes, Rui; Abramovic, Ivana; Jaspers, Roger; Pisarik, Michael; Odstrcil, Tomas; Van Oost, Guido

2015-01-01

Highlights: • We built a new diagnostic of poloidal plasma rotation on the COMPASS tokamak. • Improvements in throughput via toroidal integration and fiber optimizations shown. • Poloidal rotation and ion temperature measured in L- and H-mode and during RMP. • Design and parameters of a new CXRS diagnostic for COMPASS are introduced. - Abstract: High-resolution spectroscopy is a powerful tool for the measurement of plasma rotation as well as ion temperature using the Doppler shift of the emitted spectral lines and their Doppler broadening, respectively. Both passive and active diagnostic variants for the COMPASS tokamak are introduced. The passive diagnostic focused on the C III lines at about 465 nm is utilized for the observation of the poloidal plasma rotation. The current set-up of the measuring system is described, including the intended high-throughput optics upgrade. Different options to increase the fiber collection area are mentioned, including a flower-like fiber bundle, and the use of micro-lenses or tapered fibers. Recent measurements of poloidal plasma rotation of the order of 0–6 km/s are shown. The design of the new active diagnostic using a deuterium heating beam and based on charge exchange recombination spectroscopy (C VI line at 529 nm) is introduced. The tool will provide both space (0.5–5 cm) and time (10 ms) resolved toroidal plasma rotation and ion temperature profiles. The results of the Simulation of Spectra code used to examine the feasibility of charge exchange measurements on COMPASS are shown and connected with a selection of the spectrometer coupled with the CCD camera.

DAQ system for low density plasma parameters measurement

International Nuclear Information System (INIS)

Joshi, Rashmi S.; Gupta, Suryakant B.

2015-01-01

In various cases where low density plasmas (number density ranges from 1E4 to 1E6 cm -3 ) exist for example, basic plasma studies or LEO space environment measurement of plasma parameters becomes very critical. Conventional tip (cylindrical) Langmuir probes often result into unstable measurements in such lower density plasma. Due to larger surface area, a spherical Langmuir probe is used to measure such lower plasma densities. Applying a sweep voltage signal to the probe and measuring current values corresponding to these voltages gives V-I characteristics of plasma which can be plotted on a digital storage oscilloscope. This plot is analyzed for calculating various plasma parameters. The aim of this paper is to measure plasma parameters using a spherical Langmuir probe and indigenously developed DAQ system. DAQ system consists of Keithley source-meter and a host system connected by a GPIB interface. An online plasma parameter diagnostic system is developed for measuring plasma properties for non-thermal plasma in vacuum. An algorithm is developed using LabVIEW platform. V-I characteristics of plasma are plotted with respect to different filament current values and different locations of Langmuir probe with reference to plasma source. V-I characteristics is also plotted for forward and reverse voltage sweep generated programmatically from the source meter. (author)

Temporal variations of electron density and temperature in Kr/Ne/H2 photoionized plasma induced by nanosecond pulses from extreme ultraviolet source

Science.gov (United States)

Saber, I.; Bartnik, A.; Wachulak, P.; Skrzeczanowski, W.; Jarocki, R.; Fiedorowicz, H.

2017-06-01

Spectral investigations of low-temperature photoionized plasmas created in a Kr/Ne/H2 gas mixture were performed. The low-temperature plasmas were generated by gas mixture irradiation using extreme ultraviolet pulses from a laser-plasma source. Emission spectra in the ultraviolet/visible range from the photoionized plasmas contained lines that mainly corresponded to neutral atoms and singly charged ions. Temporal variations in the plasma electron temperature and electron density were studied using different characteristic emission lines at various delay times. Results, based on Kr II lines, showed that the electron temperature decreased from 1.7 to 0.9 eV. The electron densities were estimated using different spectral lines at each delay time. In general, except for the Hβ line, in which the electron density decreased from 3.78 × 1016 cm-3 at 200 ns to 5.77 × 1015 cm-3 at 2000 ns, most of the electron density values measured from the different lines were of the order of 1015 cm-3 and decreased slightly while maintaining the same order when the delay time increased. The time dependences of the measured and simulated intensities of a spectral line of interest were also investigated. The validity of the partial or full local thermodynamic equilibrium (LTE) conditions in plasma was explained based on time-resolved electron density measurements. The partial LTE condition was satisfied for delay times in the 200 ns to 1500 ns range. The results are summarized, and the dominant basic atomic processes in the gas mixture photoionized plasma are discussed.

Solid density, low temperature plasma formation in a capillary discharge

International Nuclear Information System (INIS)

Kania, D.R.; Jones, L.A.; Maestas, M.D.; Shepherd, R.L.

1987-01-01

This work discusses the ability of the authors to produce solid density, low temperature plasmas in polyurethane capillary discharges. The initial capillary diameter is 20 μm. The plasma is produced by discharging a one Ohm parallel plate waterline and Marx generator system through the capillary. A peak current of 340 kA in 300 ns heats the inner wall of the capillary, and the plasma expands into the surrounding material. The authors studied the evolution of the discharge using current and voltage probes, axial and radial streak photography, axial x-ray diode array and schlieren photography, and have estimated the peak temperature of the discharge to be approximately 10 eV and the density to be near 10/sup 23/cm/sup -3/. This indicates that the plasma may approach the strongly coupled regime. They discuss their interpretation of the data and compare their results with theoretical models of the plasma dynamics

Electron Temperature Fluctuation Measurements and Transport Model Validation at Alcator C-Mod

Energy Technology Data Exchange (ETDEWEB)

White, Anne [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

2017-06-22

for studying core turbulence are needed in order to assess the accuracy of gyrokinetic models for turbulent-driven particle, heat and momentum transport. New core turbulence diagnostics at the world-class tokamaks Alcator C-Mod at MIT and ASDEX Upgrade at the Max Planck Institute for Plasma Physics have been designed, developed, and operated over the course of this project. These new instruments are capable of measuring electron temperature fluctuations and the phase angle between density and temperature fluctuations locally and quantitatively. These new data sets from Alcator C-Mod and ASDEX Upgrade are being used to fill key gaps in our understanding of turbulent transport in tokamaks. In particular, this project has results in new results on the topics of the Transport Shortfall, the role of ETG turbulence in tokamak plasmas, profile stiffness, the LOC/SOC transition, and intrinsic rotation reversals. These data are used in a rigorous process of “Transport model validation”, and this group is a world-leader on using turbulence models to design new hardware and new experiments at tokamaks. A correlation electron cyclotron emission (CECE) diagnostic is an instrument used to measure micro-scale fluctuations (mm-scale, compared to the machine size of meters) of electron temperature in magnetically confined fusion plasmas, such as those in tokamaks and stellarators. These micro-scale fluctuations are associated with drift-wave type turbulence, which leads to enhanced cooling and mixing of particles in fusion plasmas and limits achieving the required temperatures and densities for self-sustained fusion reactions. A CECE system can also be coupled with a reflectometer system that measured micro-scale density fluctuations, and from these simultaneous measurements, one can extract the phase between the density (n) and temperature (T) fluctuations, creating an nT phase diagnostic. Measurements of the fluctuations and the phase angle between them are extremely useful for

Temperature dependence on plasma-induced damage and chemical reactions in GaN etching processes using chlorine plasma

Science.gov (United States)

Liu, Zecheng; Ishikawa, Kenji; Imamura, Masato; Tsutsumi, Takayoshi; Kondo, Hiroki; Oda, Osamu; Sekine, Makoto; Hori, Masaru

2018-06-01

Plasma-induced damage (PID) on GaN was optimally reduced by high-temperature chlorine plasma etching. Energetic ion bombardments primarily induced PID involving stoichiometry, surface roughness, and photoluminescence (PL) degradation. Chemical reactions under ultraviolet (UV) irradiation and chlorine radical exposure at temperatures higher than 400 °C can be controlled by taking into account the synergism of simultaneous photon and radical irradiations to effectively reduce PID.

Development of precise measurement method of neutron energy for plasma temperature diagnostics in thermonuclear fusion

International Nuclear Information System (INIS)

Mori, Chizuo; Gotoh, Junichi; Uritani, Akira; Miyahara, Hiroshi; Ikeda, Yuichiro; Kasugai, Yoshimi; Kaneko, Junichi

1998-01-01

There are many types of fast neutron spectrometers for plasma temperature diagnostics, 28 Si(n,α) 25 Mg reaction giving the energy resolution of 2.2% for 14 MeV neutrons, the 12 C(n,α) 9 Be reaction giving the resolution of 2.15%. These detectors, however suffer from radiation damage, which demands to exchange the detector to a new one in every a few month depending on the usage. Recoil proton method has also been developed by using liquid scintillator or plastic scintillator, as a neutron-to-proton converter in front of a Si-detector, which is called counter telescope type, giving a resolution of 4.0%. This type of spectrometer can reduce radiation damage by placing Si-detector at outside Neutron beam. The scintillator can measure the lost energy of protons in the converter (i.e. the scintillator) and the measured energy loss can be used for improving the energy resolution. However, the energy resolution of organic scintillator itself is generally not so good. We proposed to use a proportional counter with CH 4 as counting gas and also as a neutron-proton converter, which has far better energy resolution than plastic scintillators, although the time resolution of counting in proportional counters is generally inferior to that in organic scintillation counters. The characteristics of the new spectrometer were experimentally studied and also were simulated with analytical calculation. (author)

Improved Temperature Diagnostic for Non-Neutral Plasmas with Single-Electron Resolution

Science.gov (United States)

Shanman, Sabrina; Evans, Lenny; Fajans, Joel; Hunter, Eric; Nelson, Cheyenne; Sierra, Carlos; Wurtele, Jonathan

2016-10-01

Plasma temperature diagnostics in a Penning-Malmberg trap are essential for reliably obtaining cold, non-neutral plasmas. We have developed a setup for detecting the initial electrons that escape from a trapped pure electron plasma as the confining electrode potential is slowly reduced. The setup minimizes external noise by using a silicon photomultiplier to capture light emitted from an MCP-amplified phosphor screen. To take advantage of this enhanced resolution, we have developed a new plasma temperature diagnostic analysis procedure which takes discrete electron arrival times as input. We have run extensive simulations comparing this new discrete algorithm to our existing exponential fitting algorithm. These simulations are used to explore the behavior of these two temperature diagnostic procedures at low N and at high electronic noise. This work was supported by the DOE DE-FG02-06ER54904, and the NSF 1500538-PHY.

Spectroscopic determination of temperatures in plasmas generated by arc torches

Czech Academy of Sciences Publication Activity Database

Mašláni, Alan; Sember, Viktor; Hrabovský, Milan

2017-01-01

Roč. 133, July (2017), s. 14-20 ISSN 0584-8547 R&D Projects: GA ČR(CZ) GA15-19444S Institutional support: RVO:61389021 Keywords : Arc plasma torch * Optical emission spectroscopy * Temperature * Boltzmann plot Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 3.241, year: 2016

The determination of the electron collision cross sections for the momentum transfer in potassium by measuring the DC conductivity of a plasma

International Nuclear Information System (INIS)

Luknarova, M.; Veis, S.

1976-01-01

The DC conductivity of a thermally produced plasma in a plasma diode has been measured in pure potassium vapour. The plasma diode consists of two tungsten electrodes heated to a temperature of 2200 K. A simple theory for determining the influence of the plasma sheaths on the measured conductivity was developed and experimental conditions were established under which the potential drops across the sheaths could be neglected. By measuring the DC conductivity of the plasma at temperatures ranging from 1250 to 1600 K the potassium momentum-transfer cross section has been obtained. The measured cross section (2.37 +- 0.24) x 10 -14 cm 2 at 1500 K is in good agreement with results of other workers. Results for the work function of tungsten in potassium vapour were also obtained. (author)

Electron temperature measurements of FRX-C/LSM

International Nuclear Information System (INIS)

Rej, D.J.

1989-01-01

The electron temperature T/sub e/ has been measured with Thomson scattering field-reversed configurations (FRCs) on the Los Alamos FRX-C/LSM experiment. FRCs formed and trapped in-situ in the θ-pinch source are studied. These experiments mark the first comprehensive FRC T/sub e/ measurements in over five years with data gathered on over 400 discharges. Measurements are performed at a single point in space and time on each discharge. The Thomson scattering diagnostic consist of a Q-switched ruby laser focused from one end to a point 0.2 m from the axial midplane of the θ-pinch coil and at radius of either 0.00 or 0.10 m. Scattered light is collected, dispersed and detected with a 7-channel, triple-grating polychromator configured to detect light wavelengths between 658 and 692 nm. Photomultiplier currents are measured with gated A/D converters, with plasma background signals recorded 100-ns before and 100-ns after the laser pulse. Electron temperatures are measured at either radial position during the time interval, 10 ≤ t ≤ 70 μs, between FRC formation and the onset of the n = 2 instability which usually terminates the discharge. A variety of plasma conditions have been produced by adjusting three external parameters: the initial deuterium fill pressure p/sub O/; the reversed bias magnetic field B/sub b/; and the external magnetic field B/sub w/. The fill-pressure scan has been performed at B/sub b/ ≅ 60 mT and B/sub w/ ≅ 0.4 T with p/sub o/ set at either 2, 3, 4 or 5 mtorr. The bias-field scan, 37 ≤ B/sub b/ ≤ 95 mT, has been performed at p/sub o/ = 3 mtorr and B/sub w/ ≅ 0.4 T. 7 refs., 3 figs., 3 tabs

Direct measurements of sample heating by a laser-induced air plasma in pre-ablation spark dual-pulse laser-induced breakdown spectroscopy (LIBS).

Science.gov (United States)

Register, Janna; Scaffidi, Jonathan; Angel, S Michael

2012-08-01

Direct measurements of temperature changes were made using small thermocouples (TC), placed near a laser-induced air plasma. Temperature changes up to ~500 °C were observed. From the measured temperature changes, estimates were made of the amount of heat absorbed per unit area. This allowed calculations to be made of the surface temperature, as a function of time, of a sample heated by the air plasma that is generated during orthogonal pre-ablation spark dual-pulse (DP) LIBS measurements. In separate experiments, single-pulse (SP) LIBS emission and sample ablation rate measurements were performed on nickel at sample temperatures ranging from room temperature to the maximum surface temperature that was calculated using the TC measurement results (500 °C). A small, but real sample temperature-dependent increase in both SP LIBS emission and the rate of sample ablation was found for nickel samples heated up to 500 °C. Comparison of DP LIBS emission enhancement values for bulk nickel samples at room temperature versus the enhanced SP LIBS emission and sample ablation rates observed as a function of increasing sample temperature suggests that sample heating by the laser-induced air plasma plays only a minor role in DP LIBS emission enhancement.

Analysis and measurement of property disturbances in a combustion magnetohydrodynamic plasma

International Nuclear Information System (INIS)

Simons, T.D.; Mitchner, M.; Eustis, R.H.

1984-01-01

Measurements of propagating pressure and temperature (entropy) waves in a combustion magnetohydrodynamic (MHD) generator are presented along with a general model which describes how to produce controlled rapid property disturbances in a combustion MHD plasma. The model identifies the principal mechanisms of wave formation and predicts the qualitative and quantitative wave shapes as a function of average plasma and electrical properties but does not describe wave amplification. The model exhibits quantitatively the coupling between the entropy and acoustic waves and the electric current and magnetic field under conditions applicable to MHD power generation

Measurement of plasma parameters

International Nuclear Information System (INIS)

1999-01-01

The physics issues of the measurements of the plasma properties necessary to provide both the control and science data for achieving the goals of the ITER device are discussed. The assessment of the requirements for these measurements is first discussed, together with priorities that relate to the experimental program. Subsequently, some of the proposed measurement techniques, the plasma diagnostics, are described with particular emphasis on their implementation on ITER and their capability to meet the requirements. A judgement on the present status of the diagnostic program on ITER is provided with some indication of the research and development program necessary to demonstrate viability of techniques or their implementation. (author)

Effects of gas temperature in the plasma layer on RONS generation in array-type dielectric barrier discharge at atmospheric pressure

Science.gov (United States)

Yoon, Sung-Young; Yi, Changho; Eom, Sangheum; Park, Seungil; Kim, Seong Bong; Ryu, Seungmin; Yoo, Suk Jae

2017-12-01

In this work, we studied the control of plasma-produced species under a fixed gas composition (i.e., ambient air) in a 10 kHz-driven array-type dielectric barrier atmospheric-pressure plasma discharge. Instead of the gas composition, only the gas velocity was controlled. Thus, the plasma-maintenance cost was considerably lower than methods such as external N2 or O2 injection. The plasma-produced species were monitored using Fourier transformed infrared spectroscopy. The discharge properties were measured using a voltage probe, current probe, infrared camera, and optical emission spectroscopy. The results showed that the major plasma products largely depend on the gas temperature in the plasma discharge layer. The gas temperature in the plasma discharge layer was significantly different to the temperature of the ceramic adjacent to the plasma discharge layer, even in the small discharge power density of ˜15 W/cm2 or ˜100 W/cm3. Because the vibrational excitation of N2 was suppressed by the higher gas flow, the major plasma-produced species shifted from NOx in low flow to O3 in high flow.

Dusty plasma in a glow discharge in helium in temperature range of 5–300 K

Energy Technology Data Exchange (ETDEWEB)

Samoilov, I. S.; Baev, V. P.; Timofeev, A. V., E-mail: timofeevalvl@gmail.com; Amirov, R. Kh.; Kirillin, A. V.; Nikolaev, V. S.; Bedran, Z. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2017-03-15

Dusty plasma structures in glow discharge in helium in the temperature range of 5–300 K are investigated experimentally. We have described the experimental setup that makes it possible to continuously vary the temperature regime. The method for experimental data processing has been described. We have measured interparticle distances in the temperature range of 9–295 K and compared them with the Debye radius. We indicate the ranges of variations in experimental parameters in which plasma–dust structures are formed and various types of their behavior are manifested (rotation, vibrations of structures, formation of vertical linear chains, etc.). The applicability of the Yukawa potential to the description of the structural properties of a dusty plasma in the experimental conditions is discussed.

A diagnostic for time-resolved spatial profiles measurements on the ion temperature on JET

International Nuclear Information System (INIS)

Brocken, H.J.B.M.; Ven, H.W van der.

1980-05-01

A neutral particle scattering experiment for a continuous measurement of the ion temperature and ion density of the JET plasma in the hydrogen and deuterium phase is proposed. Space- and time-resolved measurements are possible by injection of a mono-energetic particle beam into the plasma and from the analysis of the velocity distribution of the scattered particles. The requirements on the injection system are specified and a suitable analyzer system is described

Photon-assisted Beam Probes for Low Temperature Plasmas and Installation of Neutral Beam Probe in Helimak

Science.gov (United States)

Garcia de Gorordo, Alvaro; Hallock, Gary A.; Kandadai, Nirmala

2008-11-01

The Heavy Ion Beam Probe (HIBP) diagnostic has successfully measured the electric potential in a number of major plasma devices in the fusion community. In contrast to a Langmuir probe, the HIBP measures the exact electric potential rather than the floating potential. It is also has the advantage of being a very nonperturbing diagnostic. We propose a new photon-assisted beam probe technique that would extend the HIBP type of diagnostics into the low temperature plasma regime. We expect this method to probe plasmas colder than 10 eV. The novelty of the proposed diagnostic is a VUV laser that ionizes the probing particle. Excimer lasers produce the pulsed VUV radiation needed. The lasers on the market don't have a short enough wavelength too ionize any ion directly and so we calculate the population density of excited states in a NLTE plasma. These new photo-ionization techniques can take an instantaneous one-dimensional potential measurement of a plasma and are ideal for nonmagnitized plasmas where continuous time resolution is not required. Also the status of the Neutral Beam Probe installation on the Helimak experiment will be presented.

Formation and termination of High ion temperature mode in Heliotron/torsatron plasmas

International Nuclear Information System (INIS)

Ida, K.; Kondo, K.; Nagasaki, K.

1997-01-01

Physics of the formation and termination of High ion temperature mode (high T i mode) are studied by controlling density profiles and radial electric field. High ion temperature mode is observed for neutral beam heated plasmas in Heliotron/torsatron plasmas (Heliotron-E). This high T i mode plasma is characterized by a peaked ion temperature profile and is associated with a peaked electron density profile produced by neutral beam fueling with low wall recycling. This high T i mode is terminated by flattening the electron density caused by either gas puffing or second harmonic ECH (core density 'pump-out'). (author)

Plasma fluctuation measurements in tokamaks using beam-plasma interactions (abstract)

International Nuclear Information System (INIS)

Fonck, R.J.; Duperrex, P.A.; Paul, S.F.

1990-01-01

High-frequency observations of light emitted from the interactions between plasma ions and injected neutral beam atoms allow the measurement of moderate-wavelength fluctuations in plasma and impurity ion densities. To detect turbulence in the local plasma ion density, the collisionally excited fluorescence from a neutral beam is measured either separately at several spatial points or with a multichannel imaging detector. Similarly, the role of impurity ion density fluctuations is measured using charge exchange recombination excited transitions emitted by the ion species of interest. This technique can access the relatively unexplored region of long-wavelength plasma turbulence with k perpendicular ρ i much-lt 1, and hence complements measurements from scattering experiments. Optimization of neutral beam geometry and optical sightlines can result in very good localization and resolution (Δx≤1 cm) in the hot plasma core region. The detectable fluctuation level is determined by photon statistics, atomic excitation processes, and beam stability, but can be as low as 0.2% in a 100 kHz bandwidth over the 0--1 MHz frequency range. The choices of beam species (e.g., H 0 , He 0 , etc.), observed transition (e.g., H α , L α , He I singlet or triplet transitions, C VI Δn=1, etc.) are dictated by experiment-specific factors such as optical access, flexibility of beam operation, plasma conditions, and detailed experimental goals. Initial tests on the PBX-M tokamak using the H α emissions from a heating neutral beam show low-frequency turbulence in the edge plasma region

Measuring Plasma Formation Field Strength and Current Loss in Pulsed Power Diodes

Energy Technology Data Exchange (ETDEWEB)

Johnston, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Patel, Sonal G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Falcon, Ross Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Cartwright, Keith [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Kiefer, Mark L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Cuneo, Michael E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Radiographic Technologies Dept.; Maron, Yitzhak [Weizmann Inst. of Science, Rehovot (Israel)

2017-11-01

This LDRD investigated plasma formation, field strength, and current loss in pulsed power diodes. In particular the Self-Magnetic Pinch (SMP) e-beam diode was studied on the RITS-6 accelerator. Magnetic fields of a few Tesla and electric fields of several MV/cm were measured using visible spectroscopy techniques. The magnetic field measurements were then used to determine the current distribution in the diode. This distribution showed that significant beam current extends radially beyond the few millimeter x-ray focal spot diameter. Additionally, shielding of the magnetic field due to dense electrode surface plasmas was observed, quantified, and found to be consistent with the calculated Spitzer resistivity. In addition to the work on RITS, measurements were also made on the Z-machine looking to quantify plasmas within the power flow regions. Measurements were taken in the post-hole convolute and final feed gap regions on Z. Dopants were applied to power flow surfaces and measured spectroscopically. These measurements gave species and density/temperature estimates. Preliminary B-field measurements in the load region were attempted as well. Finally, simulation work using the EMPHASIS, electromagnetic particle in cell code, was conducted using the Z MITL conditions. The purpose of these simulations was to investigate several surface plasma generations models under Z conditions for comparison with experimental data.

Correlation between Fe–V–C alloys surface hardness and plasma temperature via LIBS technique

Energy Technology Data Exchange (ETDEWEB)

Messaoud Aberkane, S., E-mail: smessaoud@cdta.dz [Centre de Développement des Technologies Avancées, Baba Hassen, Alger (Algeria); Bendib, A. [Université des Sciences et de Technologie Houari Boumediene, Bab-Ezzouar, Alger (Algeria); Yahiaoui, K.; Boudjemai, S.; Abdelli-Messaci, S.; Kerdja, T. [Centre de Développement des Technologies Avancées, Baba Hassen, Alger (Algeria); Amara, S.E. [Université des Sciences et de Technologie Houari Boumediene, Bab-Ezzouar, Alger (Algeria); Harith, M.A. [National Institute of Laser Enhanced Science, Cairo University (Egypt)

2014-05-01

Highlights: • New application of LIBS in industry. • Hardness of metallic alloys estimation using LIBS calibration curves. • Linear correlation between the plasma temperature and the hardness of metallic alloys. • The shock wave is fast when the material is hard. - Abstract: Surface hardness is a very important characteristic of metals. Its monitoring plays a key role in industry. In the present paper, using laser induced breakdown spectroscopy (LIBS), Fe–V{sub 18%}–C{sub 1%} alloys with different heat treatments have been used for making the correlation between surface hardness and laser-induced plasma temperatures. All investigated samples were characterized by the same ferrite phase with different Vickers surface hardnesses. The differences in hardness values were attributed to the crystallite size changes. A linear relationship has been obtained between the Vickers surface hardness and the laser induced plasma temperature. For comparison the relation between surface hardness and the ratio of the vanadium ionic to atomic spectral lines intensities (VII/VI) provided good linear results too. However, adopting the proposed approach of using the plasma temperature, instead, is more reliable in view of the difficulties that could be encountered in choosing the proper ionic and atomic spectral lines. To validate this approach we have investigated the shock wave speed induced by laser interaction with the used samples. It was found that harder is the material faster is the shock wave. The determination of the surface hardness via measuring T{sub e} shows the feasibility of using LIBS as an easy and reliable method for in situ industrial application for production control.

Fast Plasma Potential Measurements Using an Emissive Probe

Science.gov (United States)

Ready, Amanda; Clark, Michael; Endrizzi, Douglass; Forest, Cary; Peterson, Ethan

2017-10-01

A heated emissive probe was developed for making direct plasma potential (Vp) measurements in rapidly fluctuating plasmas. Previous experiments on the Big Red Ball (BRB) were hindered by sudden potential drops, making Langmuir measurements of the plasma potential difficult. DC heating of a tungsten filament to emission allowed for fast (4 MHz) floating potential measurements that closely matched Vp. Two BRB experiments currently use the emissive probe. The investigation of unmagnetized, collisionless shocks used plasma potential measurements to study the sub-structure of strong plasma shocks. A separate investigation of emulated magnetospheres in laboratory plasmas used the plasma potential to map the equilibria and instabilities in the electric field of such structures. Results showing electric field measurements and comparison with cold Langmuir measurements will be presented. Future plans for probe modifications and applications to other experiments on the BRB will also be shown.

Diagnostic of the temperature and differential emission measure (DEM based on Hinode/XRT data

Directory of Open Access Journals (Sweden)

P. Rudawy

2008-10-01

Full Text Available We discuss here various methodologies and an optimal strategy of the temperature and emission measure diagnostics based on Hinode X-Ray Telescope data. As an example of our results we present the determination of the temperature distribution of the X-rays emitting plasma using a filters ratio method and three various methods of the calculation of the differential emission measure (DEM. We have found that all these methods give results similar to the two filters ratio method. Additionally, all methods of the DEM calculation gave similar solutions. We can state that the majority of the pairs of the Hinode filters allows one to derive the temperature and emission measure in the isothermal plasma approximation using standard diagnostics based on the two filters ratio method. In cases of strong flares one can also expect good conformity of the results obtained using a Withbroe – Sylwester, genetic algorithm and least-squares methods of the DEM evaluation.

Low plasma edge temperatures for the self-pumped limiter

International Nuclear Information System (INIS)

Terry, W.K.; Brooks, J.N.

1985-03-01

Transport code calculations have been performed to study the operation of an INTOR-like tokamak plasma from which helium is removed by a self-pumped limiter, which traps helium, but not hydrogen, in its surface layers. To prevent saturation by helium, the surface is renewed by continuous injection of the surface material (vanadium in this study) into the scrape-off layer. The presence of the injected vanadium leads to plasma temperatures well below 50 eV in the scrape-off layer, with supplementary rf heating. Operation in this edge temperature regime is essential for the use of medium- and high-Z limiter coatings

Atomic processes in high temperature plasmas

International Nuclear Information System (INIS)

Hahn, Y.

1991-07-01

This is the final report on the project Atomic Processes in High Temperature Plasmas', which has been completed in June 30, 1991. The original contract started in 1978. The dielectronic recombination (DR) rate coefficients were calculated for ions with the number of electrons N = 1, 2, 3, 4, 5, 10, 11, and 12. The result was then used to construct a new and improved rate formula. Other important resonant processes, which are closely related to DR, were also studied to interpret experiments and to test the DR theory. The plasma field and the density effects on the rate coefficients was found to be important, and a consistent correction procedure is being developed. The available data on the DR rates and their accuracy do not yet fully meet the requirement for plasma modeling; there are serious gaps in the available data, and the currently adopted theoretical procedure needs improvements. Critical assessment of the current status of the DR problem is presented, and possible future work needed is summarized

Study on low temperature plasma driven permeation of hydrogen

Energy Technology Data Exchange (ETDEWEB)

Takizawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs.

Study on low temperature plasma driven permeation of hydrogen

International Nuclear Information System (INIS)

Takizawa, Masayuki

1998-03-01

It is one of the most important problem in PWI of fusion devices from the point of view of tritium leakage that hydrogen diffuses in the wall of the device and permeates through it, which results in hydrogen being released to the coolant side. In this study, plasma driven permeation experiments were carried out with several kinds of metal membranes in the low temperature plasma where ionic and atomic hydrogen as well as electron existed in order to survey PDP mechanism from the many view points. In addition, incident flux rate from the plasma to the membrane surface was evaluated by calculation analysis. As a result the mechanism of low temperature PDP was found out and described as PDP models. The simulation of the membrane pump system was executed and the system performance was estimated with the models. (author). 135 refs

Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission

International Nuclear Information System (INIS)

Jacquet, L.; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G.

2015-01-01

The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and

Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission

Science.gov (United States)

Jacquet, L.; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G.

2015-12-01

The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and the

Measurements and non-local thermodynamic equilibrium modeling of mid-Z plasma emission

Energy Technology Data Exchange (ETDEWEB)

Jacquet, L., E-mail: laurent.jacquet@cea.fr; Primout, M.; Kaiser, P.; Clouët, J. F.; Girard, F.; Villette, B.; Reverdin, C.; Oudot, G. [CEA, DAM, DIF, F-91297 Arpajon (France)

2015-12-15

The x-ray yields from laser-irradiated thin foils of iron, copper, zinc, and germanium have been measured in the soft and multi-keV x-ray ranges at the OMEGA laser at the Laboratory for Laser Energetics. The incident laser power had a pre-pulse to enhance the x-ray emission of a 1 ns flat-top main pulse. The experimental results have been compared with post-shot simulations performed with the two-dimensional radiation-hydrodynamics code FCI2. A new non-local thermodynamic equilibrium model, NOO-RAD, have been incorporated into FCI2. In this approach, the plasma ionization state is in-line calculated by the atomic physics NOHEL package. In the soft x-ray bands, both simulations using RADIOM [M. Busquet, Phys. Fluids B 5, 4191 (1993)] and NOO-RAD clearly over-predict the powers and energies measured by a broad-band spectrometer. In one case (the iron foil), the discrepancy between the measured and simulated x-ray output is nevertheless significantly reduced when NOO-RAD is used in the simulations. In the multi-keV x-ray bands, the simulations display a strong sensitivity to the coupling between the electron thermal conductivity and the NLTE models, and for some particular combinations of these, provide a close match to the measured emission. The comparison between the measured and simulated H-like to He-like line-intensity ratios deduced from high-resolution spectra indicates higher experimental electron temperatures were achieved, compared to the simulated ones. Measurements of the plasma conditions have been achieved using the Thomson-scattering diagnostic. The electron temperatures are found to range from 3 to 5 keV at the end of the laser pulse and are greater than predicted by the simulations. The measured flow velocities are in reasonable agreement with the calculated ones. This last finding gives us confidence in our numerical predictions for the plasma parameters, which are over that time mainly determined by hydrodynamics, such as the mass densities and

Comparative measurements of plasma potential with ball-pen and Langmuir probe in low-temperature magnetized plasma

Czech Academy of Sciences Publication Activity Database

Zanáška, M.; Adámek, Jiří; Peterka, Matěj; Kudrna, P.; Tichý, M.

2015-01-01

Roč. 22, č. 3 (2015), č. článku 033516. ISSN 1070-664X Institutional support: RVO:61389021 Keywords : plasma * tokamak * ball- pen probe (BPP) Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.207, year: 2015 http://scitation.aip.org/content/aip/journal/pop/22/3/10.1063/1.4916572

Measurement of plasma-surface energy fluxes in an argon rf-discharge by means of calorimetric probes and fluorescent microparticles

International Nuclear Information System (INIS)

Maurer, H. R.; Kersten, H.; Hannemann, M.; Basner, R.

2010-01-01

Measured energy influx densities toward a tungsten dummy substrate in an argon rf-plasma are presented and a model for the description of the energy influx density based on plasma parameters, which have been obtained by Langmuir probe measurements, is applied. Furthermore, temperature measurements of microparticles are presented, which are confined in the plasma sheath. An extension of the model is developed for the description of the energy influx density to the particles. The comparison of model and experimental results offer the possibility to obtain an improved understanding of plasma-surface interactions.

Radial Distribution Functions of Strongly Coupled Two-Temperature Plasmas

Science.gov (United States)

Shaffer, Nathaniel R.; Tiwari, Sanat Kumar; Baalrud, Scott D.

2017-10-01

We present tests of three theoretical models for the radial distribution functions (RDFs) in two-temperature strongly coupled plasmas. RDFs are useful in extending plasma thermodynamics and kinetic theory to strong coupling, but they are usually known only for thermal equilibrium or for approximate one-component model plasmas. Accurate two-component modeling is necessary to understand the impact of strong coupling on inter-species transport, e.g., ambipolar diffusion and electron-ion temperature relaxation. We demonstrate that the Seuferling-Vogel-Toeppfer (SVT) extension of the hypernetted chain equations not only gives accurate RDFs (as compared with classical molecular dynamics simulations), but also has a simple connection with the Yukawa OCP model. This connection gives a practical means to recover the structure of the electron background from knowledge of the ion-ion RDF alone. Using the model RDFs in Effective Potential Theory, we report the first predictions of inter-species transport coefficients of strongly coupled plasmas far from equilibrium. This work is supported by NSF Grant No. PHY-1453736, AFSOR Award No. FA9550-16-1-0221, and used XSEDE computational resources.

Destruction of α-synuclein based amyloid fibrils by a low temperature plasma jet

Science.gov (United States)

Karakas, Erdinc; Munyanyi, Agatha; Greene, Lesley; Laroussi, Mounir

2010-10-01

Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the "plasma pencil," a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

Destruction of α-synuclein based amyloid fibrils by a low temperature plasma jet

International Nuclear Information System (INIS)

Karakas, Erdinc; Laroussi, Mounir; Munyanyi, Agatha; Greene, Lesley

2010-01-01

Amyloid fibrils are ordered beta-sheet aggregates that are associated with a number of neurodegenerative diseases such as Alzheimer and Parkinson. At present, there is no cure for these progressive and debilitating diseases. Here we report initial studies that indicate that low temperature atmospheric pressure plasma can break amyloid fibrils into smaller units in vitro. The plasma was generated by the 'plasma pencil', a device capable of emitting a long, low temperature plasma plume/jet. This avenue of research may facilitate the development of a plasma-based medical treatment.

Confinement improvement in high-ion temperature plasmas heated with high-energy negative-NBI in LHD

International Nuclear Information System (INIS)

Takeiri, Y.; Morita, S.; Ikeda, K.

2006-10-01

The increase in the ion temperature due to transport improvement has been observed in plasmas heated with high-energy negative-NBI, in which electrons are dominantly heated, in Large Helical Device (LHD). When the centrally focused ECRH is superposed on the NBI plasma, the ion temperature is observed to rise, accompanied by formation of the electron-ITB. This is ascribed to the ion transport improvement with the transition to the neoclassical electron root with a positive radial electric field. In high-Z plasmas, the ion temperature is increased with an increase in the ion heating power, and reaches 13.5keV. The central ion temperature increases with an increase in a gradient of the electron temperature in an outer plasma region of ρ=0.8, suggesting the ion transport improvement in the outer plasma region induced by the neoclassical electron root. These results indicate the effectiveness of the electron-root scenario for obtaining high-ion temperature plasmas in helical systems. (author)

Low temperature plasma biomedicine: A tutorial review

International Nuclear Information System (INIS)

Graves, David B.

2014-01-01

Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown to be potentially useful for surface and wound sterilization, antisepsis, bleeding cessation, wound healing, and cancer treatment, among other biomedical applications. This tutorial review summarizes the field, stressing the likely role of reactive oxygen and nitrogen species created in these plasmas as the biologically and therapeutically active agents. Reactive species, including radicals and non-radical compounds, are generated naturally within the body and are now understood to be essential for normal biological functions. These species are known to be active agents in existing therapies for wound healing, infection control, and cancer treatment. But they are also observed at elevated levels in persons with many diseases and are associated with aging. The physical and chemical complexity of plasma medical devices and their associated biochemical effects makes the development of safe, effective plasma medical devices and procedures a challenge, but encouragingly rapid progress has been reported around the world in the last several years

Low temperature plasma biomedicine: A tutorial review

Energy Technology Data Exchange (ETDEWEB)

Graves, David B., E-mail: graves@berkeley.edu [University of California at Berkeley, Berkeley, California 94720 (United States)

2014-08-15

Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown to be potentially useful for surface and wound sterilization, antisepsis, bleeding cessation, wound healing, and cancer treatment, among other biomedical applications. This tutorial review summarizes the field, stressing the likely role of reactive oxygen and nitrogen species created in these plasmas as the biologically and therapeutically active agents. Reactive species, including radicals and non-radical compounds, are generated naturally within the body and are now understood to be essential for normal biological functions. These species are known to be active agents in existing therapies for wound healing, infection control, and cancer treatment. But they are also observed at elevated levels in persons with many diseases and are associated with aging. The physical and chemical complexity of plasma medical devices and their associated biochemical effects makes the development of safe, effective plasma medical devices and procedures a challenge, but encouragingly rapid progress has been reported around the world in the last several years.

Low temperature plasma biomedicine: A tutorial reviewa)

Science.gov (United States)

Graves, David B.

2014-08-01

Gas discharge plasmas formed at atmospheric pressure and near room temperature have recently been shown to be potentially useful for surface and wound sterilization, antisepsis, bleeding cessation, wound healing, and cancer treatment, among other biomedical applications. This tutorial review summarizes the field, stressing the likely role of reactive oxygen and nitrogen species created in these plasmas as the biologically and therapeutically active agents. Reactive species, including radicals and non-radical compounds, are generated naturally within the body and are now understood to be essential for normal biological functions. These species are known to be active agents in existing therapies for wound healing, infection control, and cancer treatment. But they are also observed at elevated levels in persons with many diseases and are associated with aging. The physical and chemical complexity of plasma medical devices and their associated biochemical effects makes the development of safe, effective plasma medical devices and procedures a challenge, but encouragingly rapid progress has been reported around the world in the last several years.

Measurement of the resistivity and study of the dynamics of a cold, dense plasma created in a capillary discharge

International Nuclear Information System (INIS)

Shepherd, R.L.

1987-01-01

Plasmas were created by discharging a 600-kV Marx bank across a 20μ-diameter capillary in polyurethane. The current generated by the Marx bank accretes material from the capillary wall and fills the initial void to form a plasma. Various diagnostics were fielded to help characterize the plasma. The diagnostics consist of: (1) a four channel x-ray diode array to measure the temperature, (2) schlieren photography to measure the time dependent radial size, (3) two capacitively coupled voltage probes to measure the time-dependent voltage generated by the pulse-power system and the voltage delivered across the capillary, (4) a localized Rogowski coil to measure the current through the capillary, (5) four inductive shunts to measure the return current, (6) and end-on framing and side-on visible streak photography to measure time dependent size of the visible emission. The plasmas were characterized as having densities on the order of 6 x 10 22 and temperatures of ≅ 10 eV. The peak current is reached in 270 ns at 550 kA

Fast tomographic measurements of temperature in an air plasma cutting torch

Czech Academy of Sciences Publication Activity Database

Hlína, Jan; Šonský, Jiří; Gruber, Jan; Cressault, Y.

2016-01-01

Roč. 49, č. 10 (2016), č. článku 105202. ISSN 0022-3727 Institutional support: RVO:61388998 Keywords : air plasma * cutting torch * tomography Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.588, year: 2016

Second topical conference on high-temperature plasma diagnostics

International Nuclear Information System (INIS)

Jahoda, F.C.; Freese, K.B.

1978-02-01

This report contains the program and abstracts of papers presented at the Second American Physical Society Topical Conference on High Temperature Plasma Diagnostics, March 1-3, 1978, Santa Fe, New Mexico

Scalar perturbations in two-temperature cosmological plasmas