Tearing Mode Behavior in the Globus-M Spherical Tokamak Plasma

Dudkovskaya, A.V.; Патров, М. И.; Гусев, В. К.; Курскиев, Г. С.; Petrov, Yu. V.

doi:10.1134/s1063778818070025

Cited by 2 publications

(1 citation statement)

References 6 publications

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“…With the typical plasma parameters, δB r /B T ∼ 3.5 × 10 −4 , r s ∼ 0.15 m, R = 0.75 m, B T ∼ 0.62 T, using equation ( 6), electron heat diffusivity χ S e comes about ∼20 − 25 m 2 s −1 at r = 15 cm near the location of m/n = 2/1 resonance surface. Here, the radial magnetic field component B r is calculated using the equation, B r ∼ = S a m+1 B p , where S is the distance from magnetic probe to the resonance surface and a is the minor radius of the device [60]. Moreover, recent studies have shown, that the propagation of heat pulse shows different characteristics depending on presence of magnetic island or stochastization of magnetic field [61].…”

Section: Discussionmentioning

confidence: 99%

Role of magnetohydrodynamic activity in sawtooth induced heat pulse propagation in ADITYA tokamak

Patel

Ghosh²,

Chowdhuri³

et al. 2023

Nucl. Fusion

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Fast propagation of sawtooth induced heat pulse propagation is observed in the magneto-hydrodynamic (MHD) active plasmas of ADITYA tokamak. The sawtooth crash deposits heat beyond the inversion radius, which gets transported to the edge region of the plasma and is, reflected as inverted sawtooth modulation in the edge channels of electron cyclotron emission (ECE) and Hα spectral line emission. The time-lag analysis on ECE signals reveals the propagation time from plasma core to edge of ~ 150 µs. From this analysis, the estimated transient electron heat diffusivity χe hp is found to be ~ 50 – 60 m2/s, which is ten times higher than that of power balance heat diffusivity, χe pb, in the MHD active discharges of ADITYA. It has been observed that the presence of MHD (m/n = 2/1, 3/1) activity in the intermediate region between the q = 1 and the edge radii, significantly influences the heat transport from the plasma core to the edge region. Stochastic magnetic field region formation with overlapping m/n = 2/1 and 3/1 MHD islands facilitates the fast heat-pulse propagation during a sawtooth crash in ADITYA tokamak. The disparity between the measured and the power-balance estimated diffusivity is significantly reduced by considering the heat-diffusivity due to stochastization of magnetic field in the intermediate region.

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Section: Discussionmentioning

confidence: 99%

Role of magnetohydrodynamic activity in sawtooth induced heat pulse propagation in ADITYA tokamak

Patel

Ghosh²,

Chowdhuri³

et al. 2023

Nucl. Fusion

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Investigation of Tearing Modes on the Spherical Tokamak Globus-M2 Using the Doppler Backscattering Method

et al. 2023

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In this study, we observed magnetohydrodynamic (MHD) activity of the spherical tokamak Globus-M2 which led to a deterioration in plasma confinement, such as a transition from the H-mode to L-mode, or even disruption. This instability was found to be tearing modes, which are a result of the formation of magnetic islands in plasma and which impose limits on plasma pressure. The width and velocity of the islands are key parameters that determine their impact on plasma confinement. The Doppler backscattering (DBS) method has been shown to be effective for the study of MHD activity. This method was employed on the spherical tokamak Globus-M2, together with an array of magnetic probes, to study the tearing modes. The available DBS systems allowed for simultaneous measurements from half of the minor radius to the separatrix. The results are presented of our investigation of tearing modes that lead to a transition from the H-mode or a disruption. Comparative analysis was conducted of the observed tearing modes and the influence of different plasma parameters on their development.

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Tearing Mode Behavior in the Globus-M Spherical Tokamak Plasma

Cited by 2 publications

References 6 publications

Role of magnetohydrodynamic activity in sawtooth induced heat pulse propagation in ADITYA tokamak

Role of magnetohydrodynamic activity in sawtooth induced heat pulse propagation in ADITYA tokamak

Investigation of Tearing Modes on the Spherical Tokamak Globus-M2 Using the Doppler Backscattering Method

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