A multi-machine scaling of halo current rotation

Myers, C E; Eidietis, N W; Gerasimov, S N; Gerhardt, S Pl; Granetz, R S; Hender, T C; Pautasso, G

doi:10.11578/1562022

Title: A multi-machine scaling of halo current rotation

Abstract

Halo currents generated during unmitigated tokamak disruptions are known to develop rotating asymmetric features that are of great concern to ITER because they can dynamically amplify the mechanical stresses on the machine. This paper presents a multi-machine analysis of these phenomena. More specifically, data from C-Mod, NSTX, ASDEX Upgrade, DIII-D, and JET are used to develop empirical scalings of three key quantities: (1) the machine-specific minimum current quench time, tauCQ; (2) the halo current rotation duration, trot; and (3) the average halo current rotation frequency, . These data reveal that the normalized rotation duration, trot/tauCQ, and the average rotation velocity, , are surprisingly consistent from machine to machine. Furthermore, comparisons between carbon and metal wall machines show that metal walls have minimal impact on the behavior of rotating halo currents. Finally, upon projecting to ITER, the empirical scalings indicate that substantial halo current rotation above = 20 Hz is to be expected. More importantly, depending on the projected value of tauCQ in ITER, substantial rotation could also occur in the resonant frequency range of 6-20 Hz. As such, the possibility of damaging halo current rotation during unmitigated disruptions in ITER cannot be ruled out.

Authors:: Myers, C E; Eidietis, N W; Gerasimov, S N; Gerhardt, S Pl; Granetz, R S; Hender, T C; Pautasso, G

Publication Date:: Sun Oct 01 00:00:00 EDT 2017

DOE Contract Number:: AC02-09CH11466

Research Org.:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

Sponsoring Org.:: U. S. Department of Energy

Keywords:: Halo currents

OSTI Identifier:: 1562022

DOI:: https://doi.org/10.11578/1562022

Citation Formats


                    Myers, C E, Eidietis, N W, Gerasimov, S N, Gerhardt, S Pl, Granetz, R S, Hender, T C, and Pautasso, G. A multi-machine scaling of halo current rotation.  United States: N. p., 2017. 
        Web.  doi:10.11578/1562022.

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                    Myers, C E, Eidietis, N W, Gerasimov, S N, Gerhardt, S Pl, Granetz, R S, Hender, T C, & Pautasso, G. A multi-machine scaling of halo current rotation.  United States.  doi:https://doi.org/10.11578/1562022

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                    Myers, C E, Eidietis, N W, Gerasimov, S N, Gerhardt, S Pl, Granetz, R S, Hender, T C, and Pautasso, G. 2017.  
"A multi-machine scaling of halo current rotation".  United States.  doi:https://doi.org/10.11578/1562022.  https://www.osti.gov/servlets/purl/1562022. Pub date:Sun Oct 01 00:00:00 EDT 2017

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@article{osti_1562022,

  title        = {A multi-machine scaling of halo current rotation},

  author       = {Myers, C E and Eidietis, N W and Gerasimov, S N and Gerhardt, S Pl and Granetz, R S and Hender, T C and Pautasso, G},

  abstractNote = {Halo currents generated during unmitigated tokamak disruptions are known to develop rotating asymmetric features that are of great concern to ITER because they can dynamically amplify the mechanical stresses on the machine. This paper presents a multi-machine analysis of these phenomena. More specifically, data from C-Mod, NSTX, ASDEX Upgrade, DIII-D, and JET are used to develop empirical scalings of three key quantities: (1) the machine-specific minimum current quench time, tauCQ; (2) the halo current rotation duration, trot; and (3) the average halo current rotation frequency, . These data reveal that the normalized rotation duration, trot/tauCQ, and the average rotation velocity, , are surprisingly consistent from machine to machine. Furthermore, comparisons between carbon and metal wall machines show that metal walls have minimal impact on the behavior of rotating halo currents. Finally, upon projecting to ITER, the empirical scalings indicate that substantial halo current rotation above = 20 Hz is to be expected. More importantly, depending on the projected value of tauCQ in ITER, substantial rotation could also occur in the resonant frequency range of 6-20 Hz. As such, the possibility of damaging halo current rotation during unmitigated disruptions in ITER cannot be ruled out.},

  doi          = {10.11578/1562022},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Sun Oct 01 00:00:00 EDT 2017},

  month        = {Sun Oct 01 00:00:00 EDT 2017}

}

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DOI: https://doi.org/10.11578/1562022

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