Synchrotron radiation loss from hot plasma

Tamor, S.

doi:10.1016/0168-9002(88)91123-0

Cited by 14 publications

(11 citation statements)

References 2 publications

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“…This correction factor, which has been checked in Ref. [7] and found to be valid also in the case of toroidal plasma geometry, has been included in our fit.…”

Section: Introductionmentioning

confidence: 95%

“…In the case of inhomogeneous plasmas with toroidal geometry, Tamor [7] uses a Monte Carlo code where a large number of rays are tracked throughout the plasma. This method allows a rigorous analysis of wall reflections and, associated with a radial discretization, gives access to the energy redistribution on the plasma profile, but it is much more demanding in computation time than the method described above.…”

Section: Introductionmentioning

confidence: 99%

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Improved calculation of synchrotron radiation losses in realistic tokamak plasmas

2001

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Owing to the complexity of the exact calculation, synchrotron losses are usually estimated in system studies, with expressions derived from a plasma description using simplifying assumptions on the geometry, radiation absorption, and density and temperature profiles. In the present article, a complete formulation of the transport of synchrotron radiation is performed for realistic conditions of toroidal plasma geometry with elongated cross-section, using a quasi-exact method for the calculation of the absorption coefficients, and for arbitrary shapes of density and temperature profiles. The effects of toroidicity and temperature profile on synchrotron radiation losses are analysed in detail. In particular, when the electron temperature profile is almost flat in the plasma centre as, for example, in internal transport barrier confinement regimes, synchrotron losses are found to be much stronger than in the case where the profile is represented by its best generalized parabolic approximation, though both cases give approximately the same thermal energy content. Such an effect is not included in presently used approximate expressions. As an illustration, it is shown that in the case of an advanced high temperature plasma envisaged for a steady state commercial reactor, synchrotron losses represent approximately 20% of the total losses, so that this term becomes significant in the power balance of such a plasma. Finally, the authors propose a seven variable fit for the fast calculation of synchrotron radiation losses. This fit is derived from a large database which has been generated using a code implementing the complete formulation, and is optimized for massively parallel computing.1 Unless otherwise indicated, all units are SI in the present article except for the temperature, which is always expressed in keV (k 1.6022 × 10 −16 J/keV).

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“…This correction factor, which has been checked in Ref. [7] and found to be valid also in the case of toroidal plasma geometry, has been included in our fit.…”

Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Improved calculation of synchrotron radiation losses in realistic tokamak plasmas

2001

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“…Besides direct comparison of the self-similar, (28), and exact, (27), solution transport Equation (19), an inverse problem is solved to identify the range of vari the two-dimensional space, {time, space coordinate}, where the self-similar soluti curate within 10% error bars around the exact solution. This boundary, dubbed t function of time only, i.e., for the entire range of space coordinates, is shown in Fi The minimal value, γ = 0.5, corresponds to the longest tail of the PDF of the type (26), known in physical problems (see, e.g., [16]).…”

Section: A Test Of the Proposedmentioning

confidence: 99%

Self-Similar Solutions in the Theory of Nonstationary Radiative Transfer in Spectral Lines in Plasmas and Gases

et al. 2021

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Radiative transfer (RT) in spectral lines in plasmas and gases under complete redistribution of the photon frequency in the emission-absorption act is known as a superdiffusion transport characterized by the irreducibility of the integral (in the space coordinates) equation for the atomic excitation density to a diffusion-type differential equation. The dominant role of distant rare flights (Lévy flights, introduced by Mandelbrot for trajectories generated by the Lévy stable distribution) is well known and is used to construct approximate analytic solutions in the theory of stationary RT (the escape probability method is the best example). In the theory of nonstationary RT, progress based on similar principles has been made recently. This includes approximate self-similar solutions for the Green’s function (i) at an infinite velocity of carriers (no retardation effects) to cover the Biberman–Holstein equation for various spectral line shapes; (ii) for a finite fixed velocity of carriers to cover a wide class of superdiffusion equations dominated by Lévy walks with rests; (iii) verification of the accuracy of above solutions by comparison with direct numerical solutions obtained using distributed computing. The article provides an overview of the above results with an emphasis on the role of distant rare flights in the discovery of nonstationary self-similar solutions.

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“…The plasma opacity factor depends on the density, field and plasma size as ∼ an e /B (see e.g. [52]), which slightly increases with the size of the reactor, ∼ R 1/4 , along that line. Also note that, in general, the stellarator design points feature higher densities and lower temperatures compared to the tokamak's, which result in substantially lower synchrotron radiation losses for a similar volume and field strength.…”

Section: D Analysis Of Reactor Design Points With Prescribed (N T ) P...mentioning

confidence: 99%

Physics design point of high-field stellarator reactors

Alonso,

Calvo,

Carralero

et al. 2021

Preprint

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The ongoing development of electromagnets based on High Temperature Superconductors has led to the conceptual exploration of high-magnetic-field fusion reactors of the tokamak type, operating at on-axis fields above 10 T. In this work we explore the consequences of the potential future availability of high-field three-dimensional electromagnets on the physics design point of a stellarator reactor. We find that, when an increase in the magnetic field strength B is used to maximally reduce the device linear size R ∼ B −4/3 (with otherwise fixed magnetic geometry), the physics design point is largely independent of the chosen field strength/device size. A similar degree of optimization is to be imposed on the magnetohydrodynamic, transport and fast ion confinement properties of the magnetic configuration of that family of reactor design points. Additionally, we show that the family shares an invariant operation map of fusion power output as a function of the auxiliary power and relative density variation. The effect of magnetic field over-engineering is inspected and shown to alleviate some optimization requirements while toughening others. * The helically symmetric experiment (HSX) has been shown to possess a resilient localised pattern of field-line strike points [10], but a divertor was not foreseen in its construction. * This is not to say that deviations in particular parametric dependencies of the neoclassical and turbulence diffusivities with respect to the gyro-Bohm diffusivity are excluded. The neoclassical 1/ν limit discussed before is an example of this.

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Synchrotron radiation loss from hot plasma

Cited by 14 publications

References 2 publications

Improved calculation of synchrotron radiation losses in realistic tokamak plasmas

Improved calculation of synchrotron radiation losses in realistic tokamak plasmas

Self-Similar Solutions in the Theory of Nonstationary Radiative Transfer in Spectral Lines in Plasmas and Gases

Physics design point of high-field stellarator reactors

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