TY - JOUR
T1 - Estimation of Effective Momentum Diffusivity and Its Correlation with Neutral Particle Density Based on Toroidal Rotation Profiles in the TCABR Tokamak
AU - Novaes, Douglas Oliveira
AU - Severo, José Helder Facundo
AU - Rizzato, Felipe Barbedo
AU - Ronchi, Gilson
AU - Fernandes, Tiago
AU - Ikeda, Mayara Yumi
AU - Neto, Vinícius Maia
AU - Albuquerque, Fernando
AU - do Nascimento, Fellype
AU - Iraburu, Juan
AU - de Sá, Wanderley Pires
AU - Sgubin, Leonardo Gimenes
AU - Levaton, Jacques
AU - Canal, Gustavo Paganini
AU - Filho, Zwinglio Guimarães
AU - Galvão, Ricardo Magnus Osório
AU - Tendler, Michael
N1 - Publisher Copyright:
© The Author(s) under exclusive licence to Sociedade Brasileira de Física 2024.
PY - 2025/2
Y1 - 2025/2
N2 - An equation for estimating the effective diffusivity χφeff based on the thermal and frictional forces arising from the interactions with neutral particles is provided. These interactions are primarily attributed to charge-exchange processes between ions and neutral particles. Our analysis indicates that the proposed forces are strong candidates to act as sources or sinks of momentum at the plasma edge. Furthermore, although we only have an estimated profile of neutral particles, the results demonstrate a strong dependence of the effective diffusivity on the ion-neutral collision frequency and a comparatively weaker dependence on ion temperature. We showed that the toroidal rotation profile in the TCABR tokamak is well described by the Helander model for toroidal rotation velocity in the Pfirsch-Schlüter regime, which depends on the ion temperature gradient in the presence of the neutral particles. The toroidal rotation profile has been reconstructed by a sum of Bessel functions, derived from the solution of a second-order differential equation for the toroidal velocity. In this initial study on momentum transport in TCABR, our findings indicate that χφeff—which accounts for both the diffusivity and pinch terms in the momentum equation—increases significantly in the outer plasma region. Additionally, it achieves a reasonable maximum value of approximately χφeff≈20 m2/s near the plasma edge at r/a≃0.87, in the same radial position of the maximum ion-neutral collision frequency, demonstrating that the applied method successfully captures the general behaviour of this component as reported in other works, and guiding future experimental validation.
AB - An equation for estimating the effective diffusivity χφeff based on the thermal and frictional forces arising from the interactions with neutral particles is provided. These interactions are primarily attributed to charge-exchange processes between ions and neutral particles. Our analysis indicates that the proposed forces are strong candidates to act as sources or sinks of momentum at the plasma edge. Furthermore, although we only have an estimated profile of neutral particles, the results demonstrate a strong dependence of the effective diffusivity on the ion-neutral collision frequency and a comparatively weaker dependence on ion temperature. We showed that the toroidal rotation profile in the TCABR tokamak is well described by the Helander model for toroidal rotation velocity in the Pfirsch-Schlüter regime, which depends on the ion temperature gradient in the presence of the neutral particles. The toroidal rotation profile has been reconstructed by a sum of Bessel functions, derived from the solution of a second-order differential equation for the toroidal velocity. In this initial study on momentum transport in TCABR, our findings indicate that χφeff—which accounts for both the diffusivity and pinch terms in the momentum equation—increases significantly in the outer plasma region. Additionally, it achieves a reasonable maximum value of approximately χφeff≈20 m2/s near the plasma edge at r/a≃0.87, in the same radial position of the maximum ion-neutral collision frequency, demonstrating that the applied method successfully captures the general behaviour of this component as reported in other works, and guiding future experimental validation.
KW - Momentum transport
KW - Nuclear fusion
KW - Plasma rotation
KW - Spectroscopy
KW - Tokamak
UR - http://www.scopus.com/inward/record.url?scp=85212757306&partnerID=8YFLogxK
U2 - 10.1007/s13538-024-01681-x
DO - 10.1007/s13538-024-01681-x
M3 - Article
AN - SCOPUS:85212757306
SN - 0103-9733
VL - 55
JO - Brazilian Journal of Physics
JF - Brazilian Journal of Physics
IS - 1
M1 - 43
ER -