Numerical analysis of the neutral beam attenuation rate on the HT-7 and EAST tokamaks

AbstractA diagnostic neutral beam (DNB) is applied to measure the plasma ion temperature and rotation speed in the HT-7 tokamak. Also, a heating neutral beam (HNB) is suggested as an effective method of heating a plasma for the EAST tokamak. As a necessary step to evaluate the required beam power in both applications, the attenuation of the injected neutral beam has been numerically calculated and analyzed considering the effect of various plasma parameters, such as electron temperature, electron density, impurity concentration, and so on. Three basic atomic processes are considered here. It is shown that at the same electron density neutral beam particles can penetrate deeper at higher injection energies and a DNB with the same full energy can attenuate faster at higher electron densities. The impurity effect on the attenuation of a DNB is discussed, and the attenuation of a HNB on the EAST tokamak is also considered.

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An evaluation of International Reference Ionosphere electron density in the polar cap and cusp using EISCAT Svalbard radar measurements

Annales Geophysicae ◽

10.5194/angeo-34-751-2016 ◽

2016 ◽

Vol 34 (9) ◽

pp. 751-758 ◽

Cited By ~ 11

Author(s):

Lindis Merete Bjoland ◽

Vasyl Belyey ◽

Unni Pia Løvhaug ◽

Cesar La Hoz

Keyword(s):

Electron Density ◽

Peak Height ◽

International Reference Ionosphere ◽

Ion Temperature ◽

Polar Cap ◽

Iri Model ◽

Plasma Parameters ◽

International Reference ◽

Radar Measurements

Abstract. Incoherent scatter radar measurements are an important source for studies of ionospheric plasma parameters. In this paper the EISCAT Svalbard radar (ESR) long-term database is used to evaluate the International Reference Ionosphere (IRI) model. The ESR started operations in 1996, and the accumulated database up to 2012 thus covers 16 years, giving an overview of the ionosphere in the polar cap and cusp during more than one solar cycle. Data from ESR can be used to obtain information about primary plasma parameters: electron density, electron and ion temperature, and line-of-sight plasma velocity from an altitude of about 50 and up to 1600 km. Monthly averages of electron density and temperature and ion temperature and composition are also provided by the IRI model from an altitude of 50 to 2000 km. We have compared electron density data obtained from the ESR with the predicted electron density from the IRI-2016 model. Our results show that the IRI model in general fits the ESR data well around the F2 peak height. However, the model seems to underestimate the electron density at lower altitudes, particularly during winter months. During solar minimum the model is also less accurate at higher altitudes. The purpose of this study is to validate the IRI model at polar latitudes.

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Spectroscopic Diagnostic of Cadmium Sulfide Plasma Produced By LIBS

Iraqi Journal of Physics (IJP) ◽

10.30723/ijp.v17i42.438 ◽

2019 ◽

Vol 17 (42) ◽

pp. 103-107

Author(s):

Ala' Fadhil Ahmed

Keyword(s):

Electron Temperature ◽

Cadmium Sulfide ◽

Electron Density ◽

Plasma Frequency ◽

Debye Length ◽

Emission Lines ◽

Spectral Emission ◽

Plasma Parameters ◽

Temperature Electron

Abstract The current study was carried out to reveal the plasma parameters such as ,the electron temperature ( ), electron density (ne) , plasma frequency (fp), Debye length ( ) , Debye number ( for CdS to employ the LIBS for the purpose of analyzing and determining spectral emission lines using . The results of electron temperature for CdS range (0.746-0.856) eV , the electron density(3.909-4.691)×1018 cm-3. Finally ,we discuss plasma parameters of CdS through nano second laser generated plasma .

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Current state-of-the-art for the measurement of non-Maxwellian plasma parameters with the EISCAT UHF Facility

Annales Geophysicae ◽

10.1007/s00585-996-1506-4 ◽

1996 ◽

Vol 14 (12) ◽

pp. 1506-1512 ◽

Cited By ~ 1

Author(s):

D. Hubert ◽

F. Leblanc ◽

P. Gaimard

Keyword(s):

Electron Temperature ◽

Electron Density ◽

Distribution Model ◽

Ion Temperature ◽

Ion Distribution ◽

Distribution Models ◽

Plasma Parameters ◽

Aspect Angle ◽

Complementary Measurement ◽

Incoherent Radar Spectra

Abstract. New results on the information that can be extracted from simulated non-Maxwellian incoherent radar spectra are presented. The cases of a pure ionosphere and of a composite ionosphere typical of a given altitude of the auroral F region are considered. In the case of a pure ionosphere of NO+ or O+ ions it has been shown that the electron temperature and the electron density can be derived from a Maxwellian analysis of radar spectra measured at aspect angles of 0° or 21° respectively; the ion temperature and ion temperature anisotropy can be derived from a non- constraining model such as the 1D Raman fitting of a complementary measurement made at an aspect angle larger than 0° for the NO+ ions, or at an aspect angle larger than 21° for the O+ ions. Moreover with such measurements at large aspect angles, the shape of the velocity ion distribution functions can simultaneously be inferred. The case of a composite ionosphere of atomic O+ and molecular NO+ ions is a difficult challenge which requires simultaneously a complementary measurement of the electron temperature to provide the ion composition and the electron density from the incoherent radar spectra at a specific aspect angle of 21°; hence, a model dependent routine is necessary to derive the ion temperatures and ion temperature anisotropies. In the case where the electron temperature is not given, a routine which depends on ion distribution models is required first: the better the ion distribution models are, the more accurately derived the plasma parameters will be. In both cases of a composite ionosphere, the 1D Raman fitting can be used to keep a check on the validity of the results provided by the ion distribution model dependent routine.

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Bayesian filtering for incoherent scatter radar analysis

10.5194/egusphere-egu2020-13374 ◽

2020 ◽

Author(s):

Habtamu Tesfaw ◽

Ilkka Virtanen ◽

Anita Aikio ◽

Lassi Roininen ◽

Sari Lasanen

Keyword(s):

Electron Temperature ◽

Electron Density ◽

Time Resolution ◽

Plasma Parameter ◽

Temperature Profiles ◽

Bayesian Filtering ◽

Ion Composition ◽

Ion Temperature ◽

Plasma Parameters ◽

Incoherent Scatter

Electron precipitation and ion frictional heating events cause rapid variations in electron temperature, ion temperature and F1 region ion composition of the high-latitude ionosphere. Four plasma parameters: electron density, electron temperature, ion temperature, and plasma bulk velocity, are typically fitted to incoherent scatter radar (ISR) data.Many ISR data analysis tools extract the plasma parameters using an ion composition profile from an empirical model. The modeled ion composition profile may cause bias in the estimated ion and electron temperature profiles in the F1 region, where both atomic and molecular ions exist with a temporally varying proportion.In addition, plasma parameter estimation from ISR measurements requires integrating the scattered signal typically for tens of seconds. As a result, the standard ISR observations have not been able to follow the rapid variations in plasma parameters caused by small scale auroral activity.In this project, we implemented Bayesian filtering technique to the EISCAT&#8217;s standard ISR data analysis package, GUISDAP. The technique allows us to control plasma parameter gradients in altitude and time.The Bayesian filtering implementation enabled us to fit electron density, ion and electron temperatures, ion velocity and ion composition to ISR data with high time resolution. The fitted ion composition removes observed artifacts in ion and electron temperature estimates and the plasma parameters are calculated with 5 s time resolution which was previously unattainable.Energy spectra of precipitating electrons can be calculated from electron density and electron temperature profiles observed with ISR. We used the unbiased high time-resolved electron density and temperature estimates to improve the accuracy of the estimated energy spectra. The result shows a significant difference compared to previously published results, which were based on the raw electron density (backscattered power) and electron temperature estimates calculated with coarser time resolution.&#160;

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Measurement of the electrical properties of a flowing plasma, including a critical comparison of probe experiment and theory

Journal of Plasma Physics ◽

10.1017/s0022377800004293 ◽

1969 ◽

Vol 3 (2) ◽

pp. 161-178 ◽

Cited By ~ 2

Author(s):

E. W. Billington

Keyword(s):

Major Axis ◽

Wire Mesh ◽

Ion Temperature ◽

Plasma Parameters ◽

Direct Exposure ◽

Current Voltage ◽

Double Electrode ◽

Flowing Plasma ◽

Current Voltage Characteristics ◽

Mesh Grid

The primary quantities characterizing the electricaJ carriers of a flowing plasma in a low density wind tunnel have been determined from measurements using electrostatic probes immersed in the plasma. With the exception of the ion temperature, the plasma parameters have been obtained from the current—voltage characteristics of two types of single electrode probe. The probes consist of a cylinder, the major axis of which is aligned parallel to the flow of the plasma, and a disk, the exposed surface of which is normal to the direction of flow. Experiments with a double electrode probe consisting of a disk-shaped collector electrode which is screened from direct exposure to the plasma by a fine wire mesh, grid electrode, made it possible to obtain current—voltage characteristics with the ion and electron components separated from one another. From the current—voltage characteristic corresponding to collection of ions, using the screen grid probe, values of the ion temperature and drift velocity have been obtained. The measurements have been made at various points along the centre line of flow, for one particular value of the flow rate using argon as the test gas. For a given position of the probes, one value of the ion temperature has been evaluated, together with two independent values of each of the other primary quantities characterizing the electrical carriers of a flowing plasma. Each pair of values agree satisfactorily amongst themselves, good agreement being generally obtained between probe theory and experiment.

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Machine Learning Prediction of Electron Density and Temperature from Optical Emission Spectroscopy in Nitrogen Plasma

Coatings ◽

10.3390/coatings11101221 ◽

2021 ◽

Vol 11 (10) ◽

pp. 1221

Author(s):

Jun-Hyoung Park ◽

Ji-Ho Cho ◽

Jung-Sik Yoon ◽

Jung-Ho Song

Keyword(s):

Machine Learning ◽

Electron Temperature ◽

Real Time ◽

Electron Density ◽

Emission Spectroscopy ◽

Optical Emission Spectroscopy ◽

Optical Emission ◽

Plasma Parameters ◽

Plasma Nitridation

We present a non-invasive approach for monitoring plasma parameters such as the electron temperature and density inside a radio-frequency (RF) plasma nitridation device using optical emission spectroscopy (OES) in conjunction with multivariate data analysis. Instead of relying on a theoretical model of the plasma emission to extract plasma parameters from the OES, an empirical correlation was established on the basis of simultaneous OES and other diagnostics. Additionally, we developed a machine learning (ML)-based virtual metrology model for real-time Te and ne monitoring in plasma nitridation processes using an in situ OES sensor. The results showed that the prediction accuracy of electron density was 97% and that of electron temperature was 90%. This method is especially useful in plasma processing because it provides in-situ and real-time analysis without disturbing the plasma or interfering with the process.

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