Determination of the plasma column shape in a tokamak from magnetic measurements

Deshko, G. N.; Kilovataya, T.G.; Kuznetsov, Yu.K.; Pyatov, V.N.; Yasin, I.V.

doi:10.1088/0029-5515/23/10/005

Cited by 22 publications

(15 citation statements)

References 6 publications

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“…The explicit expression for the internal multi-polar moments is evaluated as an integral of the current density J / ðh 0 ;x 0 Þ that flows inside the torus with coordinate h; The total plasma current is proportional to the sum of all the internal multi-polar moments as [12]; …”

Section: Internal and External Multi-polar Momentsmentioning

confidence: 99%

Procedure to Perform Real-Time Reconstruction of the Magnetic Flux in FTU Using RTAI Virtual Machine

Sadeghi

2011

J Fusion Energ

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One of the important topics of plasma equilibrium issue in a tokamak is to determine and reconstruct the magnetic iso-flux surfaces using plasma boundary condition (in Shafranov, Sov Phys JETP Engl Transl 37:775, 1960). The equilibrium code ODIN is based on the technique using the multi-polar moments method (in Alladio and Crisanti, Nuclear Fusion 26:1143, 1986) which results from homogeneous solution of the Grad-Shafranov equation. This method is used to reconstruct the magnetic flux and equilibrium in the Frascati Tokamak Upgrade experiment. The real-time reconstruction of the magnetic field map is important to compute quantities necessary to control the plasma. In this paper we address the procedure to perform real-time reconstruction of the magnetic flux (based on ODIN) on RTAI virtual machine. As result of the real-time implementation, we will show the time evolution of the reconstructed magnetic iso-flux surfaces.

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Section: Internal and External Multi-polar Momentsmentioning

confidence: 99%

Procedure to Perform Real-Time Reconstruction of the Magnetic Flux in FTU Using RTAI Virtual Machine

Sadeghi

2011

J Fusion Energ

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“…A quantitative evaluation of the shape of the current distribution along the plasma radius on the basis of magnetic probe readings -or by means of saddle and Rogowsky coils with a particular winding densitycan be obtained by the multipole moment method [38,46] which was originally proposed for small deviations from cylindrical symmetry. By applying various numerical methods to the processing of the magnetic measurement results, it has been possible, with parametric representation of the current distribution in a plasma with non-circular cross-section, to evaluate a number of parameters quite rapidly, within less than 1 ms and to within 10% -parameters characterizing the position and shape of the plasma, as well as pressure, internal inductance and the current density profile [47][48][49].…”

Section: Electric and Magnetic Measurementsmentioning

confidence: 99%

“…For electron density measurements in the range from 6xlO 12 cm" 3 to 1.5xlO 14 cm" 3 , a frequency range of 22-110 GHz is required. Contemporary generators are incapable of providing such a broad range of scanning, and it has accordingly been proposed that the whole range should be divided into four sub-ranges: [22][23][24][25][26][27][28][29][30][31][32][33][34][35][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50] In the experiments on TFR [78], a reflectometer with a backward-wave oscillator was used which scanned the frequency of the ordinary wave (the electric field of the wave being parallel to the toroidal magnetic field) in the range 75-110 GHz. The transmitting and receiving antennas were separate.…”

Section: Electron Density Measurementsmentioning

confidence: 99%

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Plasma diagnostics on large tokamaks

Orlinskij

Magyar

1988

Nucl. Fusion

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The main tasks of the large tokamaks which are under construction (T-15 and Tore Supra) and of those which have already been built (TFTR, JET, JT-6O and DIE-D) together with their design features which are relevant to plasma diagnostics are briefly discussed. The structural features and principal characteristics of the diagnostic systems being developed or already being used on these devices are also examined. The different diagnostic methods are described according to the physical quantities to be measured: electric and magnetic diagnostics, measurements of electron density, electron temperature, the ion components of the plasma, radiation loss measurements, spectroscopy of impurities, edge diagnostics and study of plasma stability. The main parameters of the various diagnostic systems used on the six large tokamaks are summarized in tables.

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“…This is done by least square fitting a truncated series of toroidal harmonic functions to the magnetic measurements. In principle this first step can be sufficient to determine the plasma boundary [2][3][4][5][6][7][8][9] (also see the review article 10 ). Indeed the toroidal harmonics expansion is valid anywhere in the vacuum surrounding the plasma.…”

Section: Introductionmentioning

confidence: 99%

Tokamak Plasma Boundary Reconstruction Using Toroidal Harmonics and an Optimal Control Method

Faugeras

2016

Fusion Science and Technology

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This paper proposes a new fast and stable algorithm for the reconstruction of the plasma boundary from discrete magnetic measurements taken at several locations surrounding the vacuum vessel. The resolution of this inverse problem takes two steps. In the first one we transform the set of measurements into Cauchy conditions on a fixed contour Γ O close to the measurement points. This is done by least square fitting a truncated series of toroidal harmonic functions to the measurements. The second step consists in solving a Cauchy problem for the elliptic equation satisfied by the flux in the vacuum and for the overdetermined boundary conditions on Γ O previously obtained with the help of toroidal harmonics. It is reformulated as an optimal control problem on a fixed annular domain of external boundary Γ O and fictitious inner boundary Γ I . A regularized Kohn-Vogelius cost function depending on the value of the flux on Γ I and measuring the discrepency between the solution to the equation satisfied by the flux obtained using Dirichlet conditions on Γ O and the one obtained using Neumann conditions is minimized. The method presented here has led to the development of a software, called VacTH-KV, which enables plasma boundary reconstruction in any Tokamak. 1 arXiv:1511.04723v1 [math.OC] 15 Nov 2015

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Determination of the plasma column shape in a tokamak from magnetic measurements

Cited by 22 publications

References 6 publications

Procedure to Perform Real-Time Reconstruction of the Magnetic Flux in FTU Using RTAI Virtual Machine

Procedure to Perform Real-Time Reconstruction of the Magnetic Flux in FTU Using RTAI Virtual Machine

Plasma diagnostics on large tokamaks

Tokamak Plasma Boundary Reconstruction Using Toroidal Harmonics and an Optimal Control Method

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