Abel inversion of asymmetric plasma density profile at Aditya tokamak

Joshi, Neha; Atrey, P K; Pathak, S.K.

doi:10.1088/1742-6596/208/1/012129

Cited by 10 publications

(11 citation statements)

References 2 publications

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“…The value of β was taken to be 1.75. This value of β was found to be appropriate to get the best matched T e profile for describing the observed positive and negative loop voltage spikes in similar discharges [22]. After calculating the radial profile of the density of each impurity ionization stage, the emissivity radial profile of a radiative transition from an initial state, i, to a final state, j, was calculated using following equation:…”

Section: Modeling Of the O 4+ Emissivity Profilementioning

confidence: 99%

Evaluation of an Oxygen Transport Coefficient in the Aditya Tokamak Using the Radial Profile of O4+ Emissivity and the Importance of Atomic Data Used Therein

Chowdhuri

Ghosh

Dey

et al. 2019

Atoms

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Oxygen impurity transport in the typical discharges of the Aditya tokamak was investigated using emissivity radial profile of emissivity of the spectral line (2p3p 3D3–2p3d 3F4) at 650.024 nm from the Be-like oxygen ion. This O4+ spectral line was recorded using a 1.0 m multi-track spectrometer capable of simultaneous measurements from eight lines of sight passing through the plasma. The oxygen transport coefficients were determined by reproducing the experimentally measured emissivity profiles of O4+, using a one-dimensional impurity transport code, STRAHL, and photon emissivity coefficient (PEC) belonging to that transition. The PEC values were obtained from both ADAS and NIFS atomic databases. Using both the databases, much higher values of diffusion coefficients compared to the neo-classical values were observed in both high and low magnetic field edge regions of typical Aditya tokamak Ohmic plasma. Although, almost similar profiles of diffusion coefficients were obtained using PEC values from both databases, the magnitude differs considerably. The maximum values of diffusion coefficients in the plasma edge at low field side of tokamak were ~45 and ~25 m2·s−1 when modeling was done using the ADAS and NIFS databases, respectively. Further analysis on the atomic data used in the calculation indicates that the difference in diffusion coefficients is mainly related to the variation in the values of atomic data of the two databases.

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Section: Modeling Of the O 4+ Emissivity Profilementioning

confidence: 99%

Evaluation of an Oxygen Transport Coefficient in the Aditya Tokamak Using the Radial Profile of O4+ Emissivity and the Importance of Atomic Data Used Therein

Chowdhuri

Ghosh

Dey

et al. 2019

Atoms

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“…The line averaged electron density is 1.0-3.5 × 10 19 m −3 and the core electron temperature is 300 to 700 eV. The electron density and central electron temperature are measured using a 7-channel microwave interferometer [15] and soft X-ray detectors [13], respectively. The edge density and temperature are measured using Langmuir probes [16] and spectroscopic techniques.…”

Section: Aditya Tokamak and Its Diagnosticsmentioning

confidence: 99%

“…The plasma parameters i.e., electron density (ne) and electron temperature (Te) are also used in the code as input. The radial profile of electron density is obtained from sevenchannel microwave interferometer measurements [15] spanning over the whole plasma poloidal The atomic and molecular reactions, which are included in DEGAS2 code for the present simulation, are listed in Table 1.…”

Section: Degas2 Code and Its Input Parametersmentioning

confidence: 99%

Modeling of the Hα Emission from ADITYA Tokamak Plasmas

Dey

Chowdhuri

Ghosh

et al. 2019

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The spatial profile of Hα spectrum is regularly measured using a high-resolution multi-track spectrometer in ADITYA tokamak to study the neutral particle behavior. The Monte Carlo neutral particle transport code DEGAS2 is used to model the experimental Hα spectral emissions. Through the modeling of the spectral line profile of Hα, it is found that the neutral hydrogen, which is produced from molecular hydrogen and molecular hydrogen ion dissociation processes contributes 56% to the total Hα emission, and the atoms which are produced from charge-exchange process have 30% contribution. Furthermore, the experimentally measured spatial profile of chord integrated brightness was modeled for the two plasma discharges having relatively high and low density to understand the neutral particle penetration. The presence of neutrals inside the core region of the ADITYA tokamak is mainly due to the charge-exchange process. Furthermore, it is observed that neutral particle penetration is lower in higher density discharge.

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“…To measure various plasma parameters, many types of diagnostics systems are planned to be used and homodyne microwave interferometer system (MIS) is one of them [2][3][4]. In the normal Tokamak working conditions, output of the diagnostics mounted in Tokamak has to be monitored in far away control rooms, leading to the increase in the diagnostics cable length substantially and enhancing the noise levels of the acquired signal.…”

Section: Introductionmentioning

confidence: 99%

“…In the MIS, microwave beam splits into two parts: one signal goes through a reference leg and the other goes through the plasma whose density is to be determined [2,3,[9][10][11][12]. The microwave beam originating from the Gunn diode is split by the magic-tee into an object and the reference beam.…”

Section: Introductionmentioning

confidence: 99%