Geodesic mode instability driven by electron and ion fluxes in tokamaks

Result code in IS VaVaI

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Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Geodesic mode instability driven by electron and ion fluxes in tokamaks

Original language description

Geodesic Acoustic Modes (GAM) are M=0, N=0 axisymmetric toroidal modes combined with M=1, 2 poloidal side-bands and driven by the electron and anisotropic ion pressure perturbations with the frequency omega_G^2 = (7T_i/2+2T_e)/R_0^2m_i. These modes may be important for plasma transport as it has been theoretically discussed [2] and observed in experiments [4-7]. Furthermore, they may be useful as a diagnostic tool to indicate L-H confinement transition in tokamaks [5]. Eigenmodes in the geodesic frequency range have been experimentally detected under a wide range of conditions in various tokamaks. Typically, GAM oscillations are observed during counter NB injection [7,8], but they may also appear in ohmic discharges [6,8]. The nature of the experimentally observed geodesic eigenmodes is still not clear and several different mechanisms might be responsible for their dispersion and manifest themselves in different conditions. Recently, it has been theoretically shown that GAMs may be driven by an electric current with velocity along the equilibrium magnetic field in combination with the diamagnetic drift [3]. The instability occurs only when the electron current velocity is higher than the GAM phase velocity of sidebands, V_{e0}>RqomeganHere, we extend previous studies [3] and investigate whether the parallel plasma flow can drive the GAMs via coupling with the ion drift dynamics or/and the parallel current. Finally, comparison with NB experiments in COMPASS tokamak is discussed.nnnn

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

BL - Plasma physics and discharge through gases

OECD FORD branch

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Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

EPS 2016: 43rd European Physical Society Conference on Plasma Physics

ISBN

2-914771-99-1

ISSN

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e-ISSN

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Number of pages

4

Pages from-to

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Publisher name

European Physical Society

Place of publication

Mulhouse

Event location

Leuven

Event date

Jul 4, 2016

Type of event by nationality

EUR - Evropská akce

UT code for WoS article

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