Effect of sheared flows on classical and neoclassical tearing modes

Chandra, D.; Sen, Abhijit; Kaw, P. K.; Bora, Madhurjya P.; Kruger, Scott

doi:10.1088/0029-5515/45/6/015

Cited by 56 publications

(65 citation statements)

References 23 publications

(33 reference statements)

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“…We remark also that, such stabilizing effect of out-of-plane differential flows is compatible with a similar behavior, described in Ref. [16] for a reduced MHD toroidal model.…”

Section: Discussionsupporting

confidence: 90%

“…Also, in the tokamak context, the stabilizing role of a purely toroidal flow on classical and neoclassical tearing modes has been highlighted [16] and its influence on ∆ ′ has been determined analytically [17]. Clearly, the latter two works account also for toroidal effects that are absent in the slab geometry that 2 we consider in the present paper.…”

Section: Introductionmentioning

confidence: 83%

“…(38) a relation between the growth rate g and the various parameters of the system, among which ∆ ′ , which is known from the outer solution, according to (15).…”

Section: B Inner Regionmentioning

confidence: 99%

“…Non-monotonic velocity profiles, on the other hand, have been adopted in order to show the stabilizing effect of toroidal flows against sawteeth in tokamaks [26,27]. Also, even in the absence of shear, toroidal flows, have been shown to have a stabilizing effect [16]. Thus, we consider the present analysis as the investigation of the role of a particular class of out-of-plane flows, which might be relevant, but that will need to be generalized in the future, in particular with the inclusion of shear on the resonant surface and asymmetries.…”

Section: Introductionmentioning

confidence: 99%

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Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field

2014

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To cite this version:Emanuele Tassi, Daniela Grasso, Luca Comisso. Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field. The European Physical Journal D, EDP Sciences, 2014, 68, pp.88. hal-00986611 Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field AbstractThe influence of a velocity jet, directed along a magnetic guide field, on the linear evolution of collisionless reconnection is investigated both analytically and numerically. The analysis covers both the small and large ∆ ′ regimes, with ∆ ′ indicating the standard tearing stability parameter, and is carried out, in slab geometry, by means of a reduced four-field model for magnetic reconnection accounting for two-fluid effects. Analytical dispersion relations are derived in both regimes and their predictions on the growth rates are tested against numerical simulations. In both regimes the presence of the flow is shown to have a stabilizing effect, with growth rates decreasing when increasing the amplitude of the equilibrium flow. The analytical results predict that a decrease in the growth rate could be obtained also by reducing the characteristic width of the equilibrium flow profile. Such stabilizing effects appear to be stronger in the small ∆ ′ regime. A very good quantitative agreement is found between the analytical predictions and the numerical results. As a complement to the analysis, we also consider, in the small ∆ ′ regime, the dispersion relation in the absence of equilibrium flow, which extends a previously derived dispersion relation by including a corrective term due to plasma parallel compressibility. It is shown that such correction can have a stabilizing effect and yields a better agreement with the numerical results.

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“…We remark also that, such stabilizing effect of out-of-plane differential flows is compatible with a similar behavior, described in Ref. [16] for a reduced MHD toroidal model.…”

Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 83%

“…(38) a relation between the growth rate g and the various parameters of the system, among which ∆ ′ , which is known from the outer solution, according to (15).…”

Section: B Inner Regionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field

2014

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“…[13][14][15] In the nonlinear phase, the flow shear is found to decrease the saturated island width 16 and leads to deformation of magnetic island. 17 Recently, the effect of velocity profiles on both TM and NTMs has been investigated in toroidal geometry, 18 and the differential rotation between rational surfaces is found to be stabilizing, while the toroidal velocity shear at the resonant surface is destabilizing. Besides, the effect of sheared plasma rotation on the stability of TM in an Ohmic regime is investigated.…”

Section: Introductionmentioning

confidence: 99%

Linear and nonlinear effect of sheared plasma flow on resistive tearing modes

2014

Physics of Plasmas

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Abstract. The effect of sheared plasma flow on the m/n = 2/1 tearing mode is studied numerically (m and n are the poloidal and toroidal mode numbers). It is found that in the linear phase the plasma flow with a weak or moderate shear plays a stabilizing effect on tearing mode. However, the mode is driven to be more unstable by sufficiently strong sheared flow when approaching the shear Alfvé n resonance (AR). In the nonlinear phase, a moderate (strong) sheared flow leads to a smaller (larger) saturated island width. The stabilization of tearing modes by moderate shear plasma flow is enhanced for a larger plasma viscosity and a lower Alfvé n velocity. It is also found that in the nonlinear phase AR accelerates the plasma rotation around the 2/1 rational surface but decelerates it at the AR location, and the radial location satisfying AR spreads inwards towards the magnetic axis.

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Effect of local toroidal flow on double‐tearing modes in cylindrical geometry

Zhang

Guo

et al. 2020

Contributions to Plasma Physics

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The effect of local toroidal flow (LTF) on double-tearing modes (DTMs) is investigated in cylindrical geometry using the reduced magnetohydrodynamics (RMHD) model. The results indicate that the LTF between the two rational surfaces is the dominant suppression effect on DTMs. The suppression effect is enhanced with the flow width increasing, and the DTMs become more stable with the increase of the shear of the LTF between the two rational surfaces. So, in the reversed shear magnetic field configuration, the local flow is driven between the two rational surfaces, which can effectively suppress the development of DTMs and maintain the high-performance state.

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Effect of sheared flows on classical and neoclassical tearing modes

Cited by 56 publications

References 23 publications

Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field

Linear stability analysis of collisionless reconnection in the presence of an equilibrium flow aligned with the guide field

Linear and nonlinear effect of sheared plasma flow on resistive tearing modes

Effect of local toroidal flow on double‐tearing modes in cylindrical geometry

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