Physics of GAM-initiated L-H transition in a tokamak

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Physics of GAM-initiated L-H transition in a tokamak. / Askinazi, LG; Belokurov, AA; Bulanin, VV; Gurchenko, AD; Gusakov, EZ; Kiviniemi, TP; Lebedev, SV; Kornev, VA; Korpilo, T; Krikunov, SV; Leerink, S; Machielsen, M; Niskala, P; Petrov, AV.

In: Plasma Physics and Controlled Fusion, Vol. 59, No. 1, 014037, 02.11.2016.

Research output: Contribution to journalArticleScientificpeer-review

Harvard

Askinazi, LG, Belokurov, AA, Bulanin, VV, Gurchenko, AD, Gusakov, EZ, Kiviniemi, TP, Lebedev, SV, Kornev, VA, Korpilo, T, Krikunov, SV, Leerink, S, Machielsen, M, Niskala, P & Petrov, AV 2016, 'Physics of GAM-initiated L-H transition in a tokamak' Plasma Physics and Controlled Fusion, vol. 59, no. 1, 014037. https://doi.org/10.1088/0741-3335/59/1/014037

APA

Askinazi, LG., Belokurov, AA., Bulanin, VV., Gurchenko, AD., Gusakov, EZ., Kiviniemi, TP., ... Petrov, AV. (2016). Physics of GAM-initiated L-H transition in a tokamak. Plasma Physics and Controlled Fusion, 59(1), [014037]. https://doi.org/10.1088/0741-3335/59/1/014037

Vancouver

Askinazi LG, Belokurov AA, Bulanin VV, Gurchenko AD, Gusakov EZ, Kiviniemi TP et al. Physics of GAM-initiated L-H transition in a tokamak. Plasma Physics and Controlled Fusion. 2016 Nov 2;59(1). 014037. https://doi.org/10.1088/0741-3335/59/1/014037

Author

Askinazi, LG ; Belokurov, AA ; Bulanin, VV ; Gurchenko, AD ; Gusakov, EZ ; Kiviniemi, TP ; Lebedev, SV ; Kornev, VA ; Korpilo, T ; Krikunov, SV ; Leerink, S ; Machielsen, M ; Niskala, P ; Petrov, AV. / Physics of GAM-initiated L-H transition in a tokamak. In: Plasma Physics and Controlled Fusion. 2016 ; Vol. 59, No. 1.

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@article{34f578d9566844b19ad30f6980a2e274,
title = "Physics of GAM-initiated L-H transition in a tokamak",
abstract = "Based on experimental observations using the TUMAN-3M and FT-2 tokamaks, and the results of gyrokinetic modeling of the interplay between turbulence and the geodesic acoustic mode (GAM) in these installations, a simple model is proposed for the analysis of the conditions required for L–H transition triggering by a burst of radial electric field oscillations in a tokamak. In the framework of this model, one-dimensional density evolution is considered to be governed by an anomalous diffusion coefficient dependent on radial electric field shear. The radial electric field is taken as the sum of the oscillating term and the quasi-stationary one determined by density and ion temperature gradients through a neoclassical formula. If the oscillating field parameters (amplitude, frequency, etc) are properly adjusted, a transport barrier forms at the plasma periphery and sustains after the oscillations are switched off, manifesting a transition into the high confinement mode with a strong inhomogeneous radial electric field and suppressed transport at the plasma edge. The electric field oscillation parameters required for L–H transition triggering are compared with the GAM parameters observed at the TUMAN-3M (in the discharges with ohmic L–H transition) and FT-2 tokamaks (where no clear L–H transition was observed). It is concluded based on this comparison that the GAM may act as a trigger for the L–H transition, provided that certain conditions for GAM oscillation and tokamak discharge are met.",
keywords = "H-mode, GAM, turbulence, gyrokinetic modeling, L-H transition",
author = "LG Askinazi and AA Belokurov and VV Bulanin and AD Gurchenko and EZ Gusakov and TP Kiviniemi and SV Lebedev and VA Kornev and T Korpilo and SV Krikunov and S Leerink and M Machielsen and P Niskala and AV Petrov",
year = "2016",
month = "11",
day = "2",
doi = "10.1088/0741-3335/59/1/014037",
language = "English",
volume = "59",
journal = "Plasma Physics and Controlled Fusion",
issn = "0741-3335",
number = "1",

}

RIS - Download

TY - JOUR

T1 - Physics of GAM-initiated L-H transition in a tokamak

AU - Askinazi, LG

AU - Belokurov, AA

AU - Bulanin, VV

AU - Gurchenko, AD

AU - Gusakov, EZ

AU - Kiviniemi, TP

AU - Lebedev, SV

AU - Kornev, VA

AU - Korpilo, T

AU - Krikunov, SV

AU - Leerink, S

AU - Machielsen, M

AU - Niskala, P

AU - Petrov, AV

PY - 2016/11/2

Y1 - 2016/11/2

N2 - Based on experimental observations using the TUMAN-3M and FT-2 tokamaks, and the results of gyrokinetic modeling of the interplay between turbulence and the geodesic acoustic mode (GAM) in these installations, a simple model is proposed for the analysis of the conditions required for L–H transition triggering by a burst of radial electric field oscillations in a tokamak. In the framework of this model, one-dimensional density evolution is considered to be governed by an anomalous diffusion coefficient dependent on radial electric field shear. The radial electric field is taken as the sum of the oscillating term and the quasi-stationary one determined by density and ion temperature gradients through a neoclassical formula. If the oscillating field parameters (amplitude, frequency, etc) are properly adjusted, a transport barrier forms at the plasma periphery and sustains after the oscillations are switched off, manifesting a transition into the high confinement mode with a strong inhomogeneous radial electric field and suppressed transport at the plasma edge. The electric field oscillation parameters required for L–H transition triggering are compared with the GAM parameters observed at the TUMAN-3M (in the discharges with ohmic L–H transition) and FT-2 tokamaks (where no clear L–H transition was observed). It is concluded based on this comparison that the GAM may act as a trigger for the L–H transition, provided that certain conditions for GAM oscillation and tokamak discharge are met.

AB - Based on experimental observations using the TUMAN-3M and FT-2 tokamaks, and the results of gyrokinetic modeling of the interplay between turbulence and the geodesic acoustic mode (GAM) in these installations, a simple model is proposed for the analysis of the conditions required for L–H transition triggering by a burst of radial electric field oscillations in a tokamak. In the framework of this model, one-dimensional density evolution is considered to be governed by an anomalous diffusion coefficient dependent on radial electric field shear. The radial electric field is taken as the sum of the oscillating term and the quasi-stationary one determined by density and ion temperature gradients through a neoclassical formula. If the oscillating field parameters (amplitude, frequency, etc) are properly adjusted, a transport barrier forms at the plasma periphery and sustains after the oscillations are switched off, manifesting a transition into the high confinement mode with a strong inhomogeneous radial electric field and suppressed transport at the plasma edge. The electric field oscillation parameters required for L–H transition triggering are compared with the GAM parameters observed at the TUMAN-3M (in the discharges with ohmic L–H transition) and FT-2 tokamaks (where no clear L–H transition was observed). It is concluded based on this comparison that the GAM may act as a trigger for the L–H transition, provided that certain conditions for GAM oscillation and tokamak discharge are met.

KW - H-mode

KW - GAM

KW - turbulence

KW - gyrokinetic modeling

KW - L-H transition

U2 - 10.1088/0741-3335/59/1/014037

DO - 10.1088/0741-3335/59/1/014037

M3 - Article

VL - 59

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

IS - 1

M1 - 014037

ER -

ID: 9792857