Overview of Experimental Studies on IR-T1 Tokamak (original) (raw)
Related papers
1 EX / P 4-15 Overview of Experimental Studies on IRT 1 Tokamak
2008
An overview of experimental studies on IR-T1 tokamak is presented. Several issues of plasma displacement measurement are investigated. An analytic solution of the Biot–Savart law, which is used to calculate magnetic fields created by toroidal plasma current, is presented. Results of calculations are compared with the experimental data obtained in no-plasma shots with a toroidal current-carrying coil positioned inside the vessel to simulate the plasma movements. The results show a good linear behavior of plasma position measurements. An array of Mirnov coils employed for measurement of plasma position, too. The results show that Mirnov array can not be used for this measurement without concerning high field side errors. An external resonant helical magnetic field (RHF) applied to plasma. The aim of these experiments was to understand the effect of RHF on light impurities radiation and horizontal displacement measurements. Measurements results of visible line emissions of O, C impurit...
Designing a Sine-Coil for Measurement of Plasma Displacements in IR-T1 Tokamak
AIP Conference Proceedings, 2008
A method for the measurement of the plasma position in the IR-T1 tokamak in toroidal coordinates is developed. A sine-coil, which is a Rogowski coil with a variable wiring density is designed and fabricated for this purpose. An analytic solution of the Biot-Savart law, which is used to calculate magnetic fields created by toroidal plasma current, is presented. Results of calculations are compared with the experimental data obtained in no-plasma shots with a toroidal current-carrying coil positioned inside the vessel to simulate the plasma movements. The results are shown a good linear behavior of plasma position measurements. The error is less than 2.5% and it is compared with other methods of measurements of the plasma position. This method will be used in the feedback position control system and tests of feedback controller parameters are ongoing.
Analytical and experimental approaches in plasma displacement measurement in IR-T1 tokamak
Journal of Plasma Physics, 2009
In this paper two methods for determining plasma position in the IR-T1 tokamak are presented: a multipole moments method and an analytical solution of the equilibrium problem using the Grad–Shafranov equation. Based on the multipole moments method, modified Rogowski and saddle coils were designed and constructed for measuring plasma column displacement. Good agreement in comparison between the analytical and experimental approaches in determining plasma displacement in the IR-T1 tokamak is achieved.
Review of Scientific Instruments, 2010
The modified Rogowski sine-coil ͑MRSC͒ has been designed and implemented for the plasma column horizontal displacement measurements on small IR-T1 tokamak. MRSC operation has been examined on test assembly and tokamak. Obtained results show high sensitivity to the plasma column horizontal displacement and negligible sensitivity to the vertical displacement; linearity in wide, Ϯ0.1 m, range of the displacements; and excellent, 1.5%, agreement with the results of numerical solution of Biot-Savart and magnetic flux equations.
Fusion Engineering and Design, 2011
One of the analytical solutions to the inhomogeneous Grad-Shafranov equation (GSE) is based on the well-known Solov'ev equilibrium that corresponds to source functions linear in . The GSE has been solved by this method with constraints over plasma current and poloidal beta using rectangular fixed boundary conditions . In this paper a new analytical solution to GSE by imposing constraints on the plasma current andˇp + l i /2 is presented. This method is used for plasma position determination in IR-T1 Tokamak by considering linear source functions and circular fixed boundary conditions. Plasma position is also measured by discrete magnetic probes and is compared with the analytical technique. Results comparison shows good agreement for a typical discharge in IR-T1 Tokamak.
Relations Between the Plasma Diamagnetic Effect and Plasma Basic Parameters in IR-T1 Tokamak
Journal of Fusion Energy, 2009
Determinations of the poloidal beta and plasma energy are important in tokamak plasma experiments. In this paper we presented an experimental method especially based on a diamagnetic effect for measurement of these parameters in the IR-T1 tokamak. For this purposes a diamagnetic loop (toroidal flux loop) with its compensation coil constructed and installed on outer surface of the IR-T1, and the poloidal beta and then the plasma thermal energy measured.
Overview of Resonant Helical Magnetic Field Experiments on the IR-T1 Tokamak
The experimental studies during externally applied resonant helical magnetic field (RHF) perturbation in IR-T1 tokamak have been investigated. The experiments have been done in different directions of plasma current and toroidal magnetic field to finding the role of Ip and B t direction in RHF application. The Morlet wavelet spectra, Fourier coefficient decomposition (FCD) and Singular value decomposition (SVD) analysis have been used to perform time-frequency and spatial-wave number harmonics analyses on the measured MHD fluctuations. The time evolution of poloidal and toroidal rotation velocity have been measured in the edge of plasma by using of a movable 4-pin Mach probe. In RHF application during L=2/n=1 and q(a)=3.7, the oscillations of m=2 MHD mode amplified and m=3 mode suppressed. Also by applying L=3/n=1 the m=2 MHD mode oscillations has been disappeared. The toroidal velocity changes after a short delay time of about t d =1-1.5 ms during RHF application while poloidal velocity changes just after RHF. The effect of RHF in plasma displacement measurement shown an increase in flux value about %5 for L=2, L=3 separately and about %10 for L=2&3 when apply together. Results of visible line emissions of O II , C III impurities and H α radiation with and without RHF (L=2) show that the addition of a relatively small amount of resonant helical magnetic field could be effective for improving the quality of the discharge by reducing of light impurities radiation and possible suppressing major disruptions. The resonant field induced a phase with reduced H α radiation level.
Effects of External Resonant Fields on the Tokamak Edge Plasma Fluctuations
Journal of Fusion Energy, 2013
Determinations of polo idal beta, plas ma energy, plas ma p ressure, plas ma temperature, p lasma resistance, and plasma effective atomic number are important in tokamak plas ma experiments. In this paper we describe a theoretical and experimental approach especially based on toroidal flu x loop for measurement of these parameters in presence of Rotating Helical Field (RHF) in IR-T1 tokamak. For th is purposes a diamagnetic loop with its compensation coil constructed and installed on outer surface of the IR-T1. A lso in this work we measured the plasma current, plas ma voltage, and the plas ma density fro m the Rogowski coil, po loidal flu x loop, and the Langmu ir probe measurements, respectively. Experimental results show that the addition of a relatively small amount of RHF with L=2 and L=3 modes could be effective for improving the quality of tokamak plas ma discharge by creating the steady state plasma.
Plasma Position Measurements in a Tokamak with an Iron Core Transformer
Japanese Journal of Applied Physics, 2000
Two simple methods of estimating the plasma position in a large-aspect-ratio, low-βptokamak with an iron core transformer are demonstrated: a magnetic diagnostic method and an optical method. The magnetic diagnostic method utilizes an array of magnetic pickup coils to measure the poloidal magnetic field produced by the plasma current. To include the effects of toroidicity and an iron core transformer, the correction factor was calculated with the magnetic material (or iron core) inside the calculation domain and incorporated in the analysis. The evolution of horizontal and vertical displacement of the plasma center obtained in this way is used to control the KAIST-Tokamak plasmas. To compare the plasma position estimated using the magnetic pickup coils, a simple optical method is also demonstrated on KAIST-TOKAMAK using a composite video signal from a charge-coupled device (CCD) camera. The two results are in good agreement.