Transport and confinement physics Chapter 2 of the special issue: on the path to tokamak burning plasma operation

Yoshida, M.*; McDermott, R. M.*; Angioni, C.*; Camenen, Y.*; Citrin, J.*; Jakubowski, M.*; Hughes, J. W.*; Idomura, Yasuhiro; Mantica, P.*; Mariani, A.*; et al.

Nuclear Fusion, 65(3), p.033001_1 - 033001_132, 2025/02

https://doi.org/10.1088/1741-4326/ad8ced

Progress in physics understanding and theoretical model development of plasma transport and confinement in the ITPA Transport and Confinement Topical Group since the publication of the ITER Physics Basis was summarized focusing on the contributions to ITER and burning plasma prediction and control. This paper provides a general and streamlined overview on the advances that were mainly led by the ITPA TC joint experiments and joint activities for the last 15 years. This paper starts with the scientific strategy and scope of the ITPA TC Topical group and overall picture of the major progress, followed by the progress of each research field: particle transport, impurity transport, ion and electron thermal turbulent transport, momentum transport, impact of 3D magnetic fields on transport, confinement mode transitions, global confinement, and reduced transport modeling.

Low-lying excitations in Ni

Morales, A. I.*; Benzoni, G.*; Watanabe, H.*; Nishimura, Shunji*; Browne, F.*; Daido, R.*; Doornenbal, P.*; Fang, Y.*; Lorusso, G.*; Patel, Z.*; et al.

Physical Review C, 93(3), p.034328_1 - 034328_14, 2016/03

https://doi.org/10.1103/PhysRevC.93.034328

Momentum transport studies from multi-machine comparisons

Yoshida, Maiko; Kaye, S.*; Rice, J.*; Solomon, W.*; Tala, T.*; Bell, R. E.*; Burrell, K. H.*; Ferreira, J.*; Kamada, Yutaka; McDonald, D. C.*; et al.

Nuclear Fusion, 52(12), p.123005_1 - 123005_11, 2012/11

https://doi.org/10.1088/0029-5515/52/12/123005

The purpose of this study is to find a common feature on momentum transport coefficients including diffusive and non-diffusive terms in all machines. The momentum database enables us to assess a parametric dependency of momentum transport in a wider range of dimensionless parameters related to transport. Such observation will contribute to make a scaling/modeling on momentum transport for future devices like ITER and DEMO. On the other hand, the investigation of a difference in observation by comparing the experimental conditions will give a useful information to realize what plasma parameter is the key for the momentum transport coefficients.

Inter-machine comparison of intrinsic toroidal rotation

Rice, J. E.*; Ince-Cushman, A.*; de Grassie, J. S.*; Eriksson, L.-G.*; Sakamoto, Yoshiteru; Scarabosio, A.*; Bortolon, A.*; Burrell, K. H.*; Fenzi-Bonizec, C.*; Greenwald, M. J.*; et al.

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

http://www-naweb.iaea.org/napc/physics/FEC/FEC2006/html/node200.htm#39859

Parametric scalings of the intrinsic (spontaneous, with no external momentum input) toroidal rotation observed on a large number of tokamaks have been combined with an eye toward revealing the underlying mechanism(s) and extrapolation to future devices. The intrinsic rotation velocity has been found to increase with plasma stored energy or pressure in JET, Alcator C-Mod, Tore Supra, DIII- D, JT-60U and TCV, and to decrease with increasing plasma current in some of these cases. Use of dimensionless parameters has led to a roughly unified scaling with Mach number in proportion to normalized beta, although a variety of Mach numbers works fairly well; scalings of the intrinsic rotation velocity with normalized gyro-radius or collisionality show no correlation. Whether this suggests the predominant role of MHD phenomena such as ballooning transport over turbulent processes in driving the rotation remains an open question. For an ITER discharge with =2.6, an intrinsic rotation Alfvn Mach number of M 0.02 may be expected from the above deduced scaling, possibly high enough to stabilize resistive wall modes without external momentum input.