Isotope effects on intrinsic rotation in hydrogen, deuterium and tritium plasmas

Nave, M. F. F.; Delabie, E.; Ferreira, J.; García, J.; King, D.; Lennholm, M.; Lomanowski, B.; Parra, Felix; Rodriguez-Fernandez, P.; Bernardo, J.; Baruzzo, M.; Barnes, Michael; Casson, F. J.; Hillesheim, J. C.; Huber, A.; Joffrin, E.; Kappatou, A.; Maggi, C. F.; Mauriya, A.; Meneses, L.; Romanelli, M.; Salzedas, F.

doi:10.1088/1741-4326/acbb8c

Cited by 6 publications

(3 citation statements)

References 38 publications

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“…During the fourth and fifth beam pulses (1.0 MW and 1.25 MW, respectively), the CXRS signal of the δ > 0 discharge was strongly perturbed as the plasma briefly entered an ELMy H-mode phase, explaining why a few data points are missing. [68], JET [69], ADITYA [70]), a thorough explanation this phenomenon is still missing. Curiously, TCV charges operated in limited configuration rotate in the countercurrent direction at low density, with a consequent reversal occurring in the co-current direction (see [61]), i.e.…”

Section: Intrinsic Toroidal Rotation and Plasma Confinement In Negati...mentioning

confidence: 99%

Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak

Bagnato,

Duval,

Sauter

et al. 2024

Plasma Phys. Control. Fusion

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Carbon impurity transport is studied in the TCV tokamak using a Charge Exchange Recombination (CXRS) diagnostic. TCV’s flexible shaping capabilities were exploited to extend previous impurity transport studies to negative triangularity (δ < 0). A practical way of studying light impurity transport (like C, TCV’s main impurity species due to graphite tiled walls) is to investigate the correlations between the impurity ion gradients that, in this study, highlighted significant differences between positive (PT) and negative δ (NT) plasma configurations. δ scans (−0.6 < δ < +0.6) were performed in limited configurations, but displayed little correlation between Ctemperature, rotation and density gradients for positive δ. This stiff response for δ > 0 changes for negative δ, where the evolution of ∇vtor was accompanied by variations of ∇nC over a range of negative δ, showing that transport, in NT, is affected by velocity gradients. Similar δ scans were performed with additional NBH (Neutral Beam Heating), with power steps ranging from 0.25 MW to 1.25 MW, highlighting increased momentum confinement in negative δ.Finally, the evolution of intrinsic plasma toroidal rotation across LOC/SOC (Linear to Saturated Ohmic Confinement regime) transitions was explored at δ < 0, expanding previous studies performed in TCV for δ > 0 [1]. Toroidal rotation reversal was not observed for δ < 0, despite clear LOC/SOC transitions, confirming that these two phenomena occur concomitantly only in a restricted number of cases and under specific conditions.

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Section: Intrinsic Toroidal Rotation and Plasma Confinement In Negati...mentioning

confidence: 99%

Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak

Bagnato,

Duval,

Sauter

et al. 2024

Plasma Phys. Control. Fusion

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“…In recent decades, a non-zero toroidal rotation velocity has been observed in several tokamaks worldwide without having any external momentum input [11][12][13][14]. This self-driven flow generated by the plasma itself (in the absence of any auxiliary torque input) is known as intrinsic plasma rotation or spontaneous rotation [12,15]. In a tokamak, intrinsic rotation can be observed in both toroidal and poloidal directions.…”

Section: Introductionmentioning

confidence: 99%

“…However, in the next-generation large fusion device like ITER, due to its large machine size and high density, this externally applied torque might not be able to provide sufficient momentum to rotate the burning plasma [9][10][11]. In that scenario, another mechanism to generate the torque will be required to drive the plasma [12].…”

Section: Introductionmentioning

confidence: 99%

The effect of impurity seeding on edge toroidal rotation in the ADITYA-U tokamak

Kumar,

Shah,

Chowdhuri

et al. 2024

Nucl. Fusion

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Intrinsic toroidal rotation (VΦ) has been observed from Doppler shift of C5+ Carbon line (at 529.05nm) in the edge region of ADITYA-U tokamak without any auxiliary torque input in an Ohmically heated pure Hydrogen (H2) plasma as well as H2 plasmas seeded with impurities such as neon and argon. The toroidal rotation in edge region is observed to reverse its direction with an increase in plasma current beyond Ip ~ 145-150 kA, from counter-current to co-current direction. Furthermore, a systematic decrease in the co-current Vϕ has been observed with the edge density, which tends to decrease to almost zero velocity with an increase in the edge density. The injection of medium-Z impurities like Neon and Argon is observed to influence the edge toroidal rotation significantly. In low Ip discharges, argon injection leads to a reversal of edge intrinsic rotation from counter-current to co-current direction. In high Ip discharges, both Neon and Argon seeding enhances the co-current rotation by about ~ 5 - 10 km/s, at a constant Ip compared to pure H2 discharges. Simultaneous measurements of edge radial electric field, Er shows that the Er ×Bθ flow is driving the edge toroidal rotation in ADITYA-U. With impurity injection, the Er gets modified leading to observed increase in the edge toroidal rotation.

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Further rotation reversal studies in C-Mod L-mode plasmas

Rice¹,

Cao²,

Diamond

et al. 2023

Physics of Plasmas

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Studies of core toroidal rotation reversal phenomenology in C-Mod deuterium L-mode plasmas have been expanded to include details of the dependences on plasma current and toroidal magnetic field. Rotation reversal occurs at a critical density, and universal scaling indicates that the product of ncritq95R ∼ BT/2, with ncrit in 1020/m3, R in m, and BT in T. Measurements in H and He plasmas exhibit similar behavior, including a connection with the linear Ohmic confinement/saturated Ohmic confinement transition and the cutoff for non-diffusive heat transport. Electron density and ion cyclotron range of frequencies power modulation experiments suggest that the collisionality ν* is a unifying parameter. Strong impurity puffing causes the critical density to increase, indicating that the situation is more complicated than only collisionality, perhaps involving the details of the effects of dilution on ion temperature gradient mode stability.

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Isotope effects on intrinsic rotation in hydrogen, deuterium and tritium plasmas

Cited by 6 publications

References 38 publications

Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak

Study of impurity C transport and plasma rotation in negative triangularity on the TCV tokamak

The effect of impurity seeding on edge toroidal rotation in the ADITYA-U tokamak

Further rotation reversal studies in C-Mod L-mode plasmas

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