Finite-beta equilibrium magnetic field perturbations in stellarator plasmas

Morris, Robert; Glowienka, J. C.; Neilson, G.H.; Hirshman, S. P.; Merkel, P.

doi:10.1088/0029-5515/29/12/005

Cited by 21 publications

(14 citation statements)

References 7 publications

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“…It should be noted that the dependence is nearly the same as that in Ref. [3], where a set of zero net current stellarator equilibria for the ATF torsatron has been studied. In the presence of the unidirectional current the amplitude of the m = 1 harmonic is practically independent of the current density profile.…”

Section: Results Of Numerical Calculationsmentioning

confidence: 77%

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Shchepetov¹,

Кузнецов²

1996

Nucl. Fusion

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The three dimensional (3-D) and axisymmetric (2-D) magnetic fields produced by currents flowing in plasmas that are confined in stellarators with a nearly planar geometrical axis are investigated. Using the Green's function method to solve the 3-D linear equation derived previously, a simple procedure is presented here to determine the structure of plasma induced external magnetic fields in stellarators. A detailed numerical analysis of the values of the external 3-D magnetic fields and their dependences on the plasma profiles is performed. Analytical formulas are derived that could be useful for estimations. The possibility of using the measurements of these fields for the experimental identification of the magnetohydrodynamic (MHD) equilibria is considered. Also discussed are some interesting aspects of the influence of the magnetic hump on the value of the Pfirsch-Schliiter currents (that appear in recent Heliotron-E experiments) and the influence of different features of the vacuum magnetic field on the dipole component of plasma induced field is classified. The results of calculations related to the modern experiments are presented, and the case that may be typical for future experiments is also considered.

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Section: Results Of Numerical Calculationsmentioning

confidence: 77%

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Shchepetov¹,

Кузнецов²

1996

Nucl. Fusion

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“…From the viewpoint of magnetic diagnostics, typical (or standard) configurations in conventional stellarators are not so different from those ideal cases integrally independent from the pressure. This has been proved, in particular, by direct calculations for real systems showing that the plasma shape and the measured magnetic signals respond weakly to variations of pressure profile [39][40][41]. The same features can, in fact, be seen in Refs [6][7][8]: the dependence of the calculated magnetic quantities on the profiles of the plasma pressure is very weak.…”

Section: Conventional Stellarators Configurations Independent From Pmentioning

confidence: 73%

“…But this is more of an excuse and is not the main reason for the present article, which is that with growing interest in magnetic diagnostics in stellarators [37][38][39][40][41][63][64][65][66][67] and with excessive orientation of the modern theory towards numerical simulation there arises a natural necessity for a general evaluation of the problem and for stating physically clear general criteria for evaluating any particular result. We would like to emphasize the simple idea that the measured magnetic signals are integral by their nature, and in interpreting experimental results we must take this into account.…”

Section: Resultsmentioning

confidence: 99%

Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process

Adachi¹,

Adachi²,

Ichikawa³

et al. 1991

Jpn. J. Appl. Phys.

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Restrictions on magnetic diagnostics are discussed. Being related to the integral nature of the measurable quantities, these follow from the fundamental laws of electromagnetism. A series of examples demonstrating the strength of these restrictions is analysed. The general rule is emphasized that information obtained from external magnetic measurements is insufficient for reliable evaluation of plasma current and pressure profiles in tokamaks and in stellarators. The underlying reason is that outside the plasma the self-field of the equilibrium plasma currents is determined by the boundary conditions on the plasma surface alone.

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“…For systems with high shear the pressure distribution can be determined by measuring the dipole moment of the poloidal flux. However, even in the low 0 case, this dependence is rather weak and practically disappears as 0 increases [12].…”

Section: Introductionmentioning

confidence: 92%

Is it possible to extract information on the plasma pressure profile from magnetic measurements in stellarators?

Кузнецов¹,

Shchepetov²,

Sychugov³

1994

Nucl. Fusion

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The free boundary stellarator equilibria are studied in the framework of averaged equations. The structure of external magnetic fields created by currents flowing inside the plasma column is analysed. In all cases considered the dipole component of the magnetic field (in agreement with previous investigations) can only be used to determine the volume averaged value of the parameter @ if the net toroidal current is known. For zero net current operation it is shown that the quadrupole component of the external magnetic field can be used for an estimate of the plasma pressure distribution, for example, in the framework of a one parametric set of profiles. The dependence of the external magnetic field on the current distribution for the given pressure profile is also investigated, and it is shown that there is a possibility of distinguishing at least strongly different current distributions (such as the peaked and offcentred current profiles considered here) either for a large shear system at high @ or for a device with averaged vertical elongation of the vacuum magnetic surfaces.

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Finite-beta equilibrium magnetic field perturbations in stellarator plasmas

Cited by 21 publications

References 7 publications

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process

Is it possible to extract information on the plasma pressure profile from magnetic measurements in stellarators?

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Finite-beta equilibrium magnetic field perturbations in stellarator plasmas

Cited by 21 publications

References 7 publications

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Equilibrium magnetic fields and currents in a nonaxisymmetric torus: external magnetic fields in stellarators

Surface Morphology of Tl2Ba2Ca2Cu3Oy Thin Films Prepared by Thallium Diffusion Process

Is it possible to extract information on the plasma pressure profile from magnetic measurements in stellarators?

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Surface Morphology of Tl₂Ba₂Ca₂Cu₃O_y Thin Films Prepared by Thallium Diffusion Process