Numerical Studies of Fast Pressure Crash Associated with Double Tearing Modes

Zhang, W.; W., Z.; Zhang, Haowei

doi:10.1007/s10894-020-00274-1

Cited by 2 publications

(2 citation statements)

References 60 publications

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“…To avoid confusion with the m/n = 1 kink-driven sawtooth [14][15][16][17][18], we name on-axis sawteeth as sawtooth-like behaviors or sawtooth-like oscillations in the present paper. Although the linear and nonlinear evolutions [19][20][21][22][23][24][25][26], the nonlinearly explosive growth of DTM [27][28][29][30][31][32][33][34][35][36], and DTM suppression [37][38][39][40][41][42][43][44] have been intensively investigated, the periodic oscillations associated with DTMs (i.e. sawtooth-like oscillations) are rarely numerically investigated.…”

Section: Introductionmentioning

confidence: 99%

Sawtooth-like oscillations and steady states caused by the m/n = 2/1 double tearing mode

Zhang¹,

W.²,

Zhang³

et al. 2022

Plasma Sci. Technol.

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The sawtooth-like oscillations resulting from the m/n=2/1 double tearing mode (DTM) are numerically investigated through the three-dimensional, toroidal, nonlinear resistive-MHD code (CLT). We find that the nonlinear evolution of the m/n=2/1 DTM can lead to sawtooth-like oscillations, which are similar to those driven by the kink mode. The perpendicular thermal conductivity and the external heating rate can significantly alter the behaviors of the DTM driven sawtooth-like oscillations. With a high perpendicular thermal conductivity, the system quickly evolves into a steady state with m/n=2/1 magnetic islands and helical flow. However, with a low perpendicular thermal conductivity, the system tends to exhibit sawtooth-like oscillations. With a sufficiently high or low heating rate, the system exhibits sawtooth-like oscillations, while with an intermediate heating rate, the system quickly evolves into a steady state. At the steady state, there exist the non-axisymmetric magnetic field and strong radial flow, and both are with helicity of m/n=2/1. Like the steady state with m/n=1/1 radial flow, which is beneficial for preventing the Helium ash accumulation in the core, the steady state with m/n=2/1 radial flow might also be a good candidate for the advanced steady-state operations in future fusion reactors. We also find that the behaviors of the sawtooth-like oscillations are almost independent of Tokamak geometry, which implies that the steady state with saturated m/n=2/1 islands might exist in different Tokamaks.

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Section: Introductionmentioning

confidence: 99%

Sawtooth-like oscillations and steady states caused by the m/n = 2/1 double tearing mode

Zhang¹,

W.²,

Zhang³

et al. 2022

Plasma Sci. Technol.

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“…[17] Zhang et al investigated the threshold and time scales of pressure crashes associated with DTMs. [18,19] Fast reconnection of magnetic field lines caused by DTM in off-axis sawtooth phenomena, as well as explosive bursts, have been reported in many tokamak experimental discharges with RMS configurations, including TFTR, [20,21] JT-60U, [22] Tore Supra, [23] RTP, [24] and ASDEX Upgrade [25] tokamaks. The DTM instability is inevitable for future advanced tokamaks with RMS configurations, including ITER and CFETR.…”

mentioning

confidence: 99%

Effects of Plasma Boundary Shape on Explosive Bursts Triggered by Tearing Mode in Toroidal Tokamak Plasmas with Reversed Magnetic Shear

Wang

Liu

et al. 2023

Chinese Phys. Lett.

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Numerical research is conducted to investigate the effects of plasma boundary shape on the tearing mode triggering explosive bursts in toroidal tokamak plasmas. In this work, m/n = 2/1 mode is responsible for the triggering of the explosive burst. Plasma boundary shape can be adjusted via the adjustment of the parameters triangularity δ and elongation κ. The investigations are conducted both under low β (close to zero) and under finite β regimes. In the low β regime, triangularity and elongation both have stabilizing effect on the explosive burst and the stabilizing effect of elongation is stronger. Under a large elongation (κ = 2.0), the elongation effect can evidently enhance the stabilizing effect in a positive triangularity regime, but barely affects the stabilizing effect in a negative triangularity regime. In the finite β regime, the explosive burst is delayed in comparison with that in the low β regime. Similar to the low β cases, the effects of triangularity and elongation both are stabilizing. Under a large elongation (κ = 2.0), the elongation effect can evidently enhance the stabilizing effect on the explosive burst in a positive triangularity regime, but impair the stabilizing effect in a negative triangularity regime. The explosive burst disappears in the large triangularity case (δ = 0.5), indicating that the explosive burst can be effectively prevented in experiments via carefully adjusting plasma boundary shape. Moreover, strong magnetic stochasticity appears in the negative triangularity case during the nonlinear phase.

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Numerical Studies of Fast Pressure Crash Associated with Double Tearing Modes

Cited by 2 publications

References 60 publications

Sawtooth-like oscillations and steady states caused by the m/n = 2/1 double tearing mode

Sawtooth-like oscillations and steady states caused by the m/n = 2/1 double tearing mode

Effects of Plasma Boundary Shape on Explosive Bursts Triggered by Tearing Mode in Toroidal Tokamak Plasmas with Reversed Magnetic Shear

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