Interpretation of tokamak self-consistent pressure profiles

Dyabilin, K. S.; Razumova, K.A.

doi:10.1088/0029-5515/55/5/053023

Cited by 12 publications

(29 citation statements)

References 15 publications

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“…Сохраняется ли профиль k внутри ITB, где p намного выше, чем в окружающей плазме? Как показано в [6], самоорганизация приводит к сохранению логарифмической производной профиля давления (при этом p(r), конечно, тоже сохраняется), поэтому профиль k может сохраняться и при других абсолютных значениях p. Однако барьеры обычно имеют ширину порядка 1 см, и профиль давления или его производную измерить на таком участке невозможно.…”

Section: сохранение профиля логарифмической производной давления K внunclassified

“…Наиболее простой, формальный подход реализовал К.С. Дябилин [6]. Он рассматривал плазму как неравновесную термодинамическую систему и, используя уже хорошо развитую в других областях науки методику для решения таких задач, нашёл для статистики Больцмана-Гиббса профиль логарифмической производной k 0 = 1/p c (r)dp c (r)/dr, соответствующий минимуму свободной энергии, т.е.…”

Section: Introductionunclassified

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Transport Barriers and Self-Organization of Plasmas

Razumova¹,

Лысенко²,

Timchenko³

2016

PAST-TF

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На основе представлений о самоорганизации плазмы в токамаке предлагается метод анализа характеристик турбулентного механизма, ответственного за перенос тепла по радиусу. Показано, что тепловой поток переносится преимущественно низкими модами МГД-неустойчивости. Чем больше поток, создаваемый в результате искажений профиля давления внешними факторами, тем шире спектр мод и тем меньше номер моды нижней границы спектра. Обсуждается роль мод с низкими полоидальными номерами в процессе формирования транспортных барьеров. Предлагается нетрадиционное объяснение формирования режимов с улучшенным удержанием.

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Section: сохранение профиля логарифмической производной давления K внunclassified

Section: Introductionunclassified

Transport Barriers and Self-Organization of Plasmas

Razumova¹,

Лысенко²,

Timchenko³

2016

PAST-TF

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“…Following the terminology from [5], we call parameter θ the "magnetic temperature". For the energy balance, we have [8] ∂p ∂t = ∇• θp ξ ∇ ln(p/p c ) + Q s (2) where p(r) is the plasma pressure, p c (r) is the self-organized plasma pressure, Q s is a source of heating and radiation cooling, ξ in the Smoluchowski equation describes dissipation in the turbulent system, and the transport coefficient (thermal conductivity) κ = θ/ξ. The heat flow density is given by…”

Section: Self-organizationmentioning

confidence: 99%

“…In [8,9], Dyabilin and Razumova considered the magnetic confinement system in general and obtained pressure profiles that depended on some parameter γ. Comparison of these profiles with those measured experimentally in tokamak experiments shows with good accuracy that for tokamaks L q γ ∝ , θ depends on external discharge parameters and the plasma stored energy:…”

Section: Self-organizationmentioning

confidence: 99%

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Explanation of Experimentally Observed Phenomena in Hot Tokamak Plasmas from the Nonequilibrium Thermodynamics Position

Razumova

Андреев

Kasyanova

et al. 2019

Entropy

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In studying the hot plasma behavior in tokamak devices, the classical approach for collisional processes is traditionally used. This approach leaves unexplained a number of phenomena observed in experiments related to plasma energy confinement. Further, it is well known that tokamak plasma is always turbulent and self-organized. In the present paper, we show that the nonequilibrium thermodynamics approach allows us to explain many observed dependences and paradoxes; for example, puffing of impurities results in confinement improvement if zones of plasma cooling by impurities and additional plasma heating are not overlapped. The analysis of the experimental results shows the important role of radiation losses at the plasma edge in the processes determining its total energy confinement. It is shown that the generally accepted dependence of energy confinement on plasma density is not quite adequate because it is a consequence of dependence on radiation losses. The phenomenon of the appearance of internal transport barriers and magnetic islands can also be explained by plasma self-organization. The obtained results may be taken into account when calculating the operation of a future tokamak reactor.

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Features of self-organized plasma physics in tokamaks

Razumova¹

2017

Plasma Phys. Control. Fusion

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The history of investigations the role of self-organization processes in tokamak plasma confinement is presented. It was experimentally shown that the normalized pressure profile is the same for different tokamaks. Instead of the conventional Fick equation, where the thermal flux is proportional to a pressure gradient, processes in the plasma are well described by the Dyabilanin's energy balance equation, in which the heat flux is proportional to the difference of normalized gradients for self-consistent and real pressure profiles. The transport coefficient depends on the values of heat flux, which compensates distortion of the pressure profile with external impacts. Radiative cooling of the plasma edge decreases the heat flux and improves the confinement.

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Interpretation of tokamak self-consistent pressure profiles

Cited by 12 publications

References 15 publications

Transport Barriers and Self-Organization of Plasmas

Transport Barriers and Self-Organization of Plasmas

Explanation of Experimentally Observed Phenomena in Hot Tokamak Plasmas from the Nonequilibrium Thermodynamics Position

Features of self-organized plasma physics in tokamaks

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