Relativistic mono-energetic transport coefficients in hot plasmas

Relativistic mono-energetic drift kinetic equation for hot toroidal plasmas is analyzed. For compatibility with non-relativistic description, non-canonical thermodynamic forces with the additional temperature-dependent term in the first thermodynamic force were introduced. The transport coefficients...

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Published in:Вопросы атомной науки и техники
Date:2013
Main Authors: Marushchenko, I.N., Azarenkov, N.A.
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Language:English
Published: Національний науковий центр «Харківський фізико-технічний інститут» НАН України 2013
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Online Access:https://nasplib.isofts.kiev.ua/handle/123456789/111939
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Cite this:Relativistic mono-energetic transport coefficients in hot plasmas / I.N. Marushchenko, N.A. Azarenkov // Вопросы атомной науки и техники. — 2013. — № 4. — С. 112-114. — Бібліогр.: 10 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-111939
record_format dspace
spelling Marushchenko, I.N.
Azarenkov, N.A.
2017-01-15T16:58:04Z
2017-01-15T16:58:04Z
2013
Relativistic mono-energetic transport coefficients in hot plasmas / I.N. Marushchenko, N.A. Azarenkov // Вопросы атомной науки и техники. — 2013. — № 4. — С. 112-114. — Бібліогр.: 10 назв. — англ.
1562-6016
PACS: 52.27.Ny, 52.25.Fi
https://nasplib.isofts.kiev.ua/handle/123456789/111939
Relativistic mono-energetic drift kinetic equation for hot toroidal plasmas is analyzed. For compatibility with non-relativistic description, non-canonical thermodynamic forces with the additional temperature-dependent term in the first thermodynamic force were introduced. The transport coefficients were defined as a convolution of monoenergetic transport coefficients with Maxwell-Jüttner distribution function and corresponding weight function.
Проаналізовано релятивістське моноенергетичне дрейфове кінетичне рівняння для гарячої тороїдальної плазми. Для сумісності з нерелятивістським формалізмом були введені неканонічні термодинамічні сили, що містять додатковий температурно-залежний член у першій термодинамічній силі. Коефіцієнти переносу отримані у вигляді згортка моноенергетичних коефіцієнтів переносу з функцією розподілу Максвелла- Юттнера, що описує термодинамічну рівновагу в релятивістському газі, та з відповідною ваговою функцією.
Проанализировано релятивистское моноэнергетическое дрейфовое кинетическое уравнение для горячей тороидальной плазмы. Для совместимости с нерелятивистским формализмом были введены неканонические термодинамические силы, содержащие дополнительный температурно-зависимый член в первой термодинамической силе. Коэффициенты переноса получены в виде свёртки моноэнергетических коэффициентов переноса с функцией распределения Максвелла-Юттнера, описывающей термодинамическое равновесие в релятивистском газе, и соответствующей весовой функцией.
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
Вопросы атомной науки и техники
Термоядерный синтез, коллективные процессы
Relativistic mono-energetic transport coefficients in hot plasmas
Релятивістські моноенергетичні коефіцієнти переносу в гарячій плазмі
Релятивистские моноэнергетические коэффициенты переноса в горячей плазме
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Relativistic mono-energetic transport coefficients in hot plasmas
spellingShingle Relativistic mono-energetic transport coefficients in hot plasmas
Marushchenko, I.N.
Azarenkov, N.A.
Термоядерный синтез, коллективные процессы
title_short Relativistic mono-energetic transport coefficients in hot plasmas
title_full Relativistic mono-energetic transport coefficients in hot plasmas
title_fullStr Relativistic mono-energetic transport coefficients in hot plasmas
title_full_unstemmed Relativistic mono-energetic transport coefficients in hot plasmas
title_sort relativistic mono-energetic transport coefficients in hot plasmas
author Marushchenko, I.N.
Azarenkov, N.A.
author_facet Marushchenko, I.N.
Azarenkov, N.A.
topic Термоядерный синтез, коллективные процессы
topic_facet Термоядерный синтез, коллективные процессы
publishDate 2013
language English
container_title Вопросы атомной науки и техники
publisher Національний науковий центр «Харківський фізико-технічний інститут» НАН України
format Article
title_alt Релятивістські моноенергетичні коефіцієнти переносу в гарячій плазмі
Релятивистские моноэнергетические коэффициенты переноса в горячей плазме
description Relativistic mono-energetic drift kinetic equation for hot toroidal plasmas is analyzed. For compatibility with non-relativistic description, non-canonical thermodynamic forces with the additional temperature-dependent term in the first thermodynamic force were introduced. The transport coefficients were defined as a convolution of monoenergetic transport coefficients with Maxwell-Jüttner distribution function and corresponding weight function. Проаналізовано релятивістське моноенергетичне дрейфове кінетичне рівняння для гарячої тороїдальної плазми. Для сумісності з нерелятивістським формалізмом були введені неканонічні термодинамічні сили, що містять додатковий температурно-залежний член у першій термодинамічній силі. Коефіцієнти переносу отримані у вигляді згортка моноенергетичних коефіцієнтів переносу з функцією розподілу Максвелла- Юттнера, що описує термодинамічну рівновагу в релятивістському газі, та з відповідною ваговою функцією. Проанализировано релятивистское моноэнергетическое дрейфовое кинетическое уравнение для горячей тороидальной плазмы. Для совместимости с нерелятивистским формализмом были введены неканонические термодинамические силы, содержащие дополнительный температурно-зависимый член в первой термодинамической силе. Коэффициенты переноса получены в виде свёртки моноэнергетических коэффициентов переноса с функцией распределения Максвелла-Юттнера, описывающей термодинамическое равновесие в релятивистском газе, и соответствующей весовой функцией.
issn 1562-6016
url https://nasplib.isofts.kiev.ua/handle/123456789/111939
citation_txt Relativistic mono-energetic transport coefficients in hot plasmas / I.N. Marushchenko, N.A. Azarenkov // Вопросы атомной науки и техники. — 2013. — № 4. — С. 112-114. — Бібліогр.: 10 назв. — англ.
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fulltext ISSN 1562-6016. ВАНТ. 2013. №4(86) 112 RELATIVISTIC MONO-ENERGETIC TRANSPORT COEFFICIENTS IN HOT PLASMAS I.N. Marushchenko, N.A. Azarenkov V.N. Karazin Kharkоv National University, Kharkov, Ukraine E-mail: i.marushchenko@gmail.com Relativistic mono-energetic drift kinetic equation for hot toroidal plasmas is analyzed. For compatibility with non-relativistic description, non-canonical thermodynamic forces with the additional temperature-dependent term in the first thermodynamic force were introduced. The transport coefficients were defined as a convolution of mono- energetic transport coefficients with Maxwell-Jüttner distribution function and corresponding weight function. PACS: 52.27.Ny, 52.25.Fi INTRODUCTION Non-relativistic neoclassical theory for toroidal de- vices is commonly considered to be a matured field of research given the extensive body of scientific literature dealing with the topic [1, 2]. One of the most convenient computational methods developed inside the theory for determining neoclassical contributions to the transport of plasma observables such as density, temperature and current is the mono-energetic approach, which leads to the so-called mono-energetic transport coefficients (see, for example, [3] and the references therein). In contrast to the widespread opinion [1, 2] that rela- tivistic effects in fusion plasmas can be important only for high-energetic groups of electrons with energies close to me0c2 or exceeding it (say, runaway electrons), relativistic effects was found to produce the non- negligible contribution in collisional transport properties of plasmas for the temperatures about few tens keV due to the features of relativistic thermodynamic equilibrium of electrons [4 - 7]. In order to take these effects into account, one needs to reformulate the mono-energetic drift kinetic equation and the definition of transport co- efficients. In this paper, we derive the neoclassical mono- energetic transport coefficients for relativistic electrons in hot plasmas. Rigorous relativistic description gener- ally requires a covariant formulation [8]. However, while Lorentz invariance is not important for neoclassi- cal transport because the latter is limited to relatively small characteristic velocities, non-covariant formula- tion is better suited for the task since our goal is to keep the form of equations as close as possible to the formu- lation generally accepted in non-relativistic neoclassical theory. This approach allows us to calculate the relativ- istic mono-energetic transport coefficients using already existed mono-energetic non-relativistic transport codes like DKES [9]. Apart from this, it may be considered as the tool for estimation of the applicability range of non- relativistic neoclassical approach. In section 2, relativistic mono-energetic drift kinetic equation is formulated and a set of non-canonical ther- modynamic forces is introduced. It is shown that for compatibility with non-relativistic description it is nec- essary to include the explicit temperature dependence in the first thermodynamic force. In section 3, the transport coefficients are derived as a convolution of mono- energetic coefficients with the relativistic Maxwell- Jüttner distribution function and corresponding relativis- tic weight function. 1. MONO-ENERGETIC LINEAR DRIFT KINETIC EQUATION FOR RELATIVISTIC ELECTRONS Similar to the non-relativistic consideration [1 - 3], in order to obtain the neoclassical mono-energetic trans- port coefficients for relativistic electrons in hot plasmas (the ions are taken as non-relativistic) on the given magnetic surface with label ρ, we start from the lin- earized relativistic drift kinetic equation (rDKE) for deviation from the equilibrium, fe1 = fe – fe0, induced by gradients of thermodynamic quantities. Using the vari- ables (u,ξ), where u = vγ is the momentum per unit mass with γ = (1+u2/c2)1/2, ξ = (u·B)/(uB) is the pitch and B is the vector of the magnetic field, the mono-energetic rDKE can be written as ( ) 1 1 0 0 ( ) ( ) ( ) , − ν = ∂ ξ ⋅ − ⋅∇ρ − ∂ρ γ E BV e D e e dr e e V f u L f f u e f T B (1) where V = Vdr·∇s + ξ& ∂/∂ξ is the mono-energetic Vlasov operator, 2 2 (1 )+ ( ) , 2s cEu uV B B B ρ⎛ ⎞ξ − ξ ∂ = ∇ρ× ⋅∇ − ⋅∇⎜ ⎟γ γ ∂ξ⎝ ⎠ h h B (2) h = B/B is the magnetic field unit vector, ∇s is a gradi- ent within the magnetic surface, E = Eφ + Eρ∇ρ is the electric field separated to the toroidal (inductive) field Eφ and the radial field, Eρ = -∂Φ/∂ρ with Φ as plasma potential; L = (1/2)∂/∂ξ((1-ξ2)∂/∂ξ) is the Lorentz opera- tor which describes the pitch-angle scattering of elec- trons and νD(u) is the relativistic electron deflection frequency [10]. The radial component of the relativistic drift velocity can be represented as 2 2 0 3 (1 ) ( ) . 2 + ξ ρ ≡ ⋅∇ρ = ×∇ ⋅∇ρ γ & V Be dr m cu B e B (3) In order to exclude the local dependencies which do not contribute to transport, the local equilibrium fe0 can be represented as follows [9]: 0 2 2 1 ' , l e eMJ e ef Bdl f T B B ⎛ ⎞⎛ ⎞⋅⋅⎜ ⎟⎜ ⎟= + − ⎜ ⎟⎜ ⎟⎝ ⎠⎝ ⎠ ∫ E BE B (4) where the angle brackets 〈...〉 denote the flux-surface average and the relativistic thermodynamic equilibrium feMJ is given by Maxwell-Jüttner distribution function, ( 1) 3/2 3 ( ) ,re eMJ MJ r th nf C e u −μ γ−= μ π (5) ISSN 1562-6016. ВАНТ. 2013. №4(86) 113 with Boltzmann factor, / 0 ee T e en n e Φ= , included. Here, uth = pth/me0 is the thermal momentum per unit mass with pth = (2me0Te)1/2, μr = me0c2/Te and 2 2 151 (1/ ), 2 ( ) 8 r MJ r r r r eC O K −μπ = = − + μ μ μ μ (6) with Kn the modified Bessel function of n-th order. Then, the right-hand-side of Eq. (1) can be written as 2 ln ln3 , 2 eMJ e e e eMJ e u eRHS Bf T B eEn TR f T ρ ⋅ξ = − γ ⎡ ⎤∂ ∂⎛ ⎞−ρ − + − κ +⎜ ⎟⎢ ⎥∂ρ ∂ρ⎝ ⎠⎣ ⎦ E B & (7) where κ = μr(γ - 1) is the relativistic kinetic energy, normalized by temperature, and 23 2 5 151 (1/ ) 2 8r r r KR O K ⎛ ⎞ = μ − − = + μ⎜ ⎟ μ⎝ ⎠ (8) is the relativistic correction term which appears due to the specific feature of Maxwell-Jüttner distribution function [4 - 7]. Now, let us introduce the relativistic thermodynamic forces as follows: 1 2 3 2 ln ln3( ) , 2 ln( ) , ( ) . e e e e e eEn TA R T TA eA T B ρ∂ ∂⎛ ⎞ρ = − + +⎜ ⎟∂ρ ∂ρ⎝ ⎠ ∂ ρ = ∂ρ ⋅ ρ = E B (9) They are similar to the non-relativistic “canonical” thermodynamic forces, but there is one very important difference: in contrast to the “canonical” definition, where only the dependencies from the local gradients are present, A1 contains an additional relativistic factor R and thus represents an explicit function of the electron temperature Te. Finally, we obtain the mono-energetic rDKE, which can be solved by the DKES code [9]: [ ]1 2 3 + ( ) ( ) ( ) ( ) . ργ⎛ ⎞ γν ξ ∇ρ× ⋅∇ − =⎜ ⎟ ⎝ ⎠ γ − ρ ρ + κ ρ − ξ ρ h h & D s e e eMJ eMJ Ec f L f B u u A A f BA f u (10) Due to the lack of derivatives of fe1 with respect to u and ρ in Eq. (10), their values can be treated as parame- ters that leads to a considerable simplification of the drift kinetic equation from five phase-space variables to three (two angles at the magnetic surface and pitch). Similar to the non-relativistic formulation [3], solution of Eq. (10) is defined only by parameters γEρ/u and γνD(u)/u, which are, actually, nothing else as Eρ/v and νD/v, respectively. This approach is sufficient to cover the main features of the neoclassical radial transport when applied for calculations of the transport coeffi- cients and fluxes. 2. RELATIVISTIC MONO-ENERGETIC TRANSPORT COEFFICIENTS Similar to [3], let us look for the solution of Eq. (10) as [ ]0 1 1 2 0 3 ˆ ˆ ,= + κ +d e eMJ e eMJ e R u f A A f f R A f g u (11) where R0 is the reference value of the torus major ra- dius, ud = me0c2/(2eγR0B0) is characteristic of the radial drift velocity and B0 is the reference value of magnetic field strength. Then the original drift kinetic equation splits into a system of two independent dimensionless differential equations: 0 0 0 0 ˆ ˆ( ) ( ) ( ) , ˆ ˆ( ) ( ) ( ) , γ γ γ − ν = − ρ γ γ − ν = −ξ &e D e d e D e R R V f u L f u u u R R V g u L g b u u (12) with b = B/B0. Here, first equation describes the radial transport due to radial gradients, contained in A1 and A2, and second equation describes the parallel transport due to a parallel electric field, contained in A3 (the factor γ in the Eq. (12) for êf is kept with the only purpose to keep the form of equations as similar as possible to the corresponding non-relativistic equations). Within neoclassical formalism, the relationships be- tween the flux-surface-averaged fluxes, Ii, and the ther- modynamic forces which drive them, Ai, can then be expressed as 3 1 , = = − ∑i e i j j j I n L A (13) where Lij is the matrix of transport coefficients. As was shown in [5], the relativistic flux-surface- averaged flow I1, which is related to the radial compo- nent of the particle flux density, Γe , can be written in the same form as the non-relativistic one, 3 1 1 .= ⋅∇ρ = ρ∫Γ &e eI d u f (14) Next, I2, which is the radial component of the energy flux density, Qe , is equal 3 2 1 .= ⋅∇ρ = κρ∫ Q &e e e I d u f T (15) And the last, I3, is the parallel component of the electron current density, Je , is equal 3 3 1 0 . ⋅ = = ξ γ∫ J Be e uI d u b f eB (16) Expressing the fluxes Ii through the thermodynamic forces, the mono-energetic solutions of Eq. (12) may be used to determine the transport coefficients by energy convolution with the local Maxwell-Jüttner distribution function, 32 1( ) ( ) , 2i j MJ r i j i jL C d e D h h−κ γ + = μ κ κ γ κ π ∫ (17) where h1 = h3 = 1, h2 = κ and Dij(κ) are the mono- energetic transport coefficients, defined below. If one compares the expression for relativistic energy convolu- tion given by Eq. (17) to the corresponding non- relativistic formula [3], one may find that an additional ISSN 1562-6016. ВАНТ. 2013. №4(86) 114 relativistic factor ( 1) / 2γ γ + appears under integral, along with expected normalization coefficient CMJ(μr), which arise from Maxwell-Jüttner distribution function and the use of relativistic kinetic energy, κ = μr(γ - 1), instead of non-relativistic one, K = me0v 2/2Te. Finally, the relativistic mono-energetic transport co- efficients Dij for electrons are defined here as follows: 2 10 11 12 21 22 1 10 13 23 1 10 31 32 1 10 33 1 ˆ , 2 ˆ , 2 ˆ , 2 ˆ . 2 + − + − + − + − ρ = = = = − ξ ρ = = − ξ = = − ξξ γ = − ξξ γ ∫ ∫ ∫ ∫ & & d e d d e d d e d e u R D D D D d f u u u R D D d g u u R D D d b f u R D d bg (18) Of these mono-energetic coefficients, D11 is related for description of the radial transport, D33 of the parallel transport, D13 is characteristic of the Ware pinch and D31 of the bootstrap current. Only three of these coeffi- cients are independent, however, as D13 = −D31 due to Onsager symmetry. CONCLUSIONS Following the standard approach to neoclassical the- ory, the relativistic mono-energetic drift-kinetic equa- tion for hot electrons is considered. Due to a specific features of the Maxwell-Jüttner distribution function, the relativistic correction term appears in the first ther- modynamic force. By splitting the mono-energetic rDKE in two independent equations which correspond to the different thermodynamic forces, the set of trans- port coefficients is obtained. Using this scheme, relativ- istic transport coefficients can be found by re- interpretation of the solution from the non-relativistic transport codes. The solution of rDKE for given values of γEρ/u and γνD(u)/u and velocity γ/u = v, should be interpreted as the same non-relativistic function of pitch-angle with different velocity v and parameters Eρ/v and νD(u)/v, such that these parameters should co- incide numerically. Then the transport coefficients can be calculated through the convolution of mono- energetic transport coefficients with Maxwell-Jüttner distribution function and specific relativistic weight factor. REFERENCES 1. F.L. Hinton, R.D. Hazeltine. Theory of plasma transport in toroidal confinement systems // Review of Modern Physics (48). 1976, № 2, p. 239-308. 2. P. Helander, D.J. Siegmar. Collisional Transport in Magnetized Plasmas. Cambridge: «Cambridge Uni- versity Press», 2002. 3. C.D. Beidler et al. Benchmarking of the mono- energetic transport coefficients // Nuclear Fusion (51). 2011, 076001 (28 p.). 4. I. Marushchenko, N.A. Azarenkov, N.B. Marush- chenko. On stability of collisional coupling between relativistic electrons and ions in hot plasmas // Physical Plasmas (19). 2012, 112109 (4 p.). 5. I. Marushchenko, N.A. Azarenkov. Relativistic transport equations in toroidal plasmas // The Jour- nal of Kharkov National University. Series “Nuclei, particles, fields” (56). 2012, № 4, p. 29-34. 6. I. Marushchenko, N.A. Azarenkov, N.B. Marushch- enko. Relativistic neoclassical fluxes in hot plas-mas // Problems of Atomic Science and Technology. Series “Plasma Physics” (19). 2013, № 1(83), p. 67-69. 7. I. Marushchenko, N.A. Azarenkov, N.B. Marush- chenko. Relativistic neoclassical radial fluxes in the 1/ν regime // Plasma Physics & Controlled Fusion (55) (accepted for publication in 2013). 8. S.R. de Groot, W.A. van Leeuwen, Ch.G. van Weert. Relativistic kinetic theory. Amsterdam: «North-Holland Publishing Company», 1980. 9. S.P. Hirshman et al. Plasma transport coefficients for nonsymmetric toroidal confinement systems // Physical Fluids (29). 1986, № 9, p. 2951-2959. 10. B.J. Braams, Ch.F.F. Karney. Conductivity of a rela- tivistic plasma // Physical Fluids B (1). 1989, № 7, p. 1355-1368. Article received 16.05.2013 РЕЛЯТИВИСТСКИЕ МОНОЭНЕРГЕТИЧЕСКИЕ КОЭФФИЦИЕНТЫ ПЕРЕНОСА В ГОРЯЧЕЙ ПЛАЗМЕ И.Н. Марущенко, Н.А. Азаренков Проанализировано релятивистское моноэнергетическое дрейфовое кинетическое уравнение для горячей тороидальной плазмы. Для совместимости с нерелятивистским формализмом были введены неканонические термодинамические силы, содержащие дополнительный температурно-зависимый член в первой термоди- намической силе. Коэффициенты переноса получены в виде свёртки моноэнергетических коэффициентов переноса с функцией распределения Максвелла-Юттнера, описывающей термодинамическое равновесие в релятивистском газе, и соответствующей весовой функцией. РЕЛЯТИВІСТСЬКІ МОНОЕНЕРГЕТИЧНІ КОЕФІЦІЄНТИ ПЕРЕНОСУ В ГАРЯЧІЙ ПЛАЗМІ І.М. Марущенко, М.О. Азарєнков Проаналізовано релятивістське моноенергетичне дрейфове кінетичне рівняння для гарячої тороїдальної плазми. Для сумісності з нерелятивістським формалізмом були введені неканонічні термодинамічні сили, що містять додатковий температурно-залежний член у першій термодинамічній силі. Коефіцієнти переносу отримані у вигляді згортка моноенергетичних коефіцієнтів переносу з функцією розподілу Максвелла- Юттнера, що описує термодинамічну рівновагу в релятивістському газі, та з відповідною ваговою функцією.