Identification of the ubiquitous Coriolis momentum pinch in JET tokamak plasmas

Weisen, H.; Camenen, Y.; Salmi, A.; Versloot, T.; Vries, P. de; Maslov, M.; Tala, T.; Beurskens, M.; Giroud, C.

doi:10.1088/0029-5515/52/4/042001

Cited by 23 publications

(25 citation statements)

References 21 publications

(20 reference statements)

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“…This is in qualitative agreement with the predicted trends of the inward turbulent equipartition [63] and Coriolis [64] momentum pinches, which scale as R/L n . Scaling of the momentum pinch with R/L n is commonly observed [39,[65][66][67][68][69][70]. For the discharge of figure 20, R/L n at Table 2.…”

Section: Columns 3-7)mentioning

confidence: 76%

Effects of LHRF on toroidal rotation in Alcator C-Mod plasmas

Rice¹,

Podpaly²,

Reinke³

et al. 2013

Nucl. Fusion

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Application of lower hybrid range of frequencies (LHRF) waves can induce both co-and counter-current directed changes in toroidal rotation in Alcator C-Mod plasmas, depending on the target plasma current, electron density, confinement regime and magnetic shear. For ohmic L-mode discharges with good core LH wave absorption, and significant current drive at a fixed LH power near 0.8 MW, the interior (r/a < 0.5) rotation increments (on a time scale of order the current relaxation time) in the counter-current direction if n e (10 20 m −3) > q 95 /11.5, and in the co-current direction if n e (10 20 m −3) < q 95 /11.5. All discharges with co-current rotation changes have q 0 > 1, indicating a good correlation with driven current fraction, unifying the results observed on various tokamaks. For high density (n e 1.2 × 10 20 m −3) L-mode target discharges, where core LH wave absorption is low, the rotation change is in the co-current direction, but evolves on a shorter momentum transport time scale, and is seen across the entire spatial profile. For H-mode target plasmas, both co-and counter-current direction increments have been observed with LHRF. The H-mode co-rotation is correlated with the pedestal temperature gradient, which itself is enhanced by the LH waves absorbed in the plasma periphery. The H-mode counter-rotation increment, a flattening of the peaked velocity profile in the core, is consistent with a reduction in the momentum pinch correlated with a steepening of the core density profile. Most of these rotation changes must be due to indirect transport effects of LH waves on various parameters, which modify the momentum flux.

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Section: Columns 3-7)mentioning

confidence: 76%

Effects of LHRF on toroidal rotation in Alcator C-Mod plasmas

Rice¹,

Podpaly²,

Reinke³

et al. 2013

Nucl. Fusion

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“…We selected the same JET discharges of the first deuterium-tritium-experiment campaign (DTE1) which were analysed in (see also Thomas et al 1998;Thomas 2001;Weisen et al 2014). They have two important features.…”

Section: Evidence Of Enhanced Plasma Rotation In Jet Dte1 Experiments...mentioning

confidence: 99%

“…The outward energy channelling could be responsible for this (Kolesnichenko et al 2010a,b;Belova et al 2017), although there was also an alternative explanation of these experiments that an anomalous diffusivity was generated by multiple modes (Gorelenkov et al 2010). On the other hand, according to , inward SC of alpha-particle energy by fast magnetoacoustic modes (FMM, known also as CAE) with frequencies either above or approximately the ion gyrofrequency may have played a role in the improved confinement and anomalous ion heating, which seems took place in JET DTE1 experiments with deuterium-tritium (D-T) plasmas (Thomas et al 1998;Thomas 2001;Weisen et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Momentum transfer and plasma rotation caused by destabilized eigenmodes in tokamaks

Kolesnichenko

Kim²,

Lutsenko³

et al. 2022

J. Plasma Phys.

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The influence of magnetohydrodynamic eigenmodes destabilized by energetic ions on the momentum of these ions and concomitant sheared plasma rotation are studied. Two mechanisms affecting rotation are revealed: (i) spatial channelling (SC) – radially separated emission and absorption of the momentum; (ii) mode induced redistribution (MIR) across the magnetic field of the momentum of energetic ions. Forces arising during SC and MIR produce both toroidal and poloidal rotations. In addition, the momentum emission during SC leads to a radial flux of fast ions and generation of a radial electric field. Using the developed theory, estimates were made for the ITER (International Thermonuclear Experimental Reactor) 15 MA baseline scenario. They show that a global toroidicity-induced Alfvén eigenmode destabilized by alpha particles and neutral beam injection can result in significant radial electric field and forces applied to plasma. However, available data are not sufficient for a reliable prediction of the effects of SC and MIR in ITER. In general, one can expect that sheared rotation arising after destabilization of Alfvén modes and fast magnetoacoustic modes by energetic ions will tend to suppress the turbulence and improve plasma performance. The importance of plasma rotation is supported, in particular, by the fact that during the JET DTE1 experimental campaign the best parameters were achieved in a deuterium–tritium discharge where the rotation frequency was largest.

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“…The investigations have been carried out with torque modulation experiments, produced by modulation of the NBI power [12,79,80,81,82,101,83,84,85,86], or by means of transients of the toroidal velocity due to a plasma brake induced by the application of nonresonant magnetic perturbations [87,81,88]. More recently, an alternative approach based on the analysis of a large data base of stationary phases of beam heated plasmas at JET has also allowed the identification of the presence of a convective mechanism through an extended statistical analysis, and the main dependences of this convective component have been singled out by means of multivariate regressions [89,90]. These works have produced an experimental characterization of the phenomenology, and can be considered to be part of step (a) described in Section 2.…”

Section: Validation Of Theoretical Predictions Of Turbulent Toroidal mentioning

confidence: 99%

Particle and Momentum Transport in Tokamak Plasmas, the Complicated Path towards the Experimental Validation of the Theoretical Predictions of Transport in Fusion Plasmas

Angioni

2013

Plasma and Fusion Research

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Recent research on turbulent transport of particle and toroidal momentum in the core of tokamak plasmas is reviewed. Similarities and differences between these two transport channels are briefly presented, highlighting the common feature that both include large off-diagonal components in the radial flux. The main goal of the review is to provide selected recent examples of validation studies in these topical areas, and, thereby, to outline an efficient route to validation in the complex field of transport studies dedicated to transport channels which include important off-diagonal components.

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Identification of the ubiquitous Coriolis momentum pinch in JET tokamak plasmas

Cited by 23 publications

References 21 publications

Effects of LHRF on toroidal rotation in Alcator C-Mod plasmas

Effects of LHRF on toroidal rotation in Alcator C-Mod plasmas

Momentum transfer and plasma rotation caused by destabilized eigenmodes in tokamaks

Particle and Momentum Transport in Tokamak Plasmas, the Complicated Path towards the Experimental Validation of the Theoretical Predictions of Transport in Fusion Plasmas

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