Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T

Schmidtmayr, M.; Hughes, J. W.; Ryter, F.; Wolfrum, E.; Cao, N.; Creely, A. J.; Howard, N.; Hubbard, A. E.; Lin, Y.; Reinke, M. L.; Rice, J. E.; Tolman, E. A.; Wukitch, S.; Ma, Y.

doi:10.7910/DVN/FSSICO

Title: Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T

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Abstract

This paper presents investigations on the role of the edge ion heat flux for transitions from L-mode to H-mode in Alcator C-Mod. Previous results from the ASDEX Upgrade tokamak indicated that a critical value of edge ion heat flux per particle is needed for the transition. Analysis of C-Mod data confirms this result. The edge ion heat flux is indeed found to increase linearly with density at given magnetic field and plasma current. Furthermore, the Alcator C-Mod data indicate that the edge ion heat flux at the L-H transition also increases with magnetic field. Combining the data from Alcator C-Mod and ASDEX Upgrade yields a general expression for the edge ion heat flux at the L-H transition. These results are discussed from the point of view of the possible physics mechanism of the L-H transition. They are also compared to the L-H power threshold scaling and an extrapolation for ITER is given.

Authors:

Schmidtmayr, M.; Hughes, J. W.; Ryter, F.; Wolfrum, E.; Cao, N.; Creely, A. J.; Howard, N.; Hubbard, A. E.; Lin, Y.; Reinke, M. L.; Rice, J. E.; Tolman, E. A.; Wukitch, S.; Ma, Y.

OSTI

Publication Date:: Thu Oct 04 00:00:00 EDT 2018

DOE Contract Number:: FC02-99ER54512; SC0014264

Research Org.:: Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center

Sponsoring Org.:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Collaborations:: ASDEX Upgrade Team; Alcator C-Mod Team

Subject:: 70 PLASMA PHYSICS AND FUSION TECHNOLOGY

OSTI Identifier:: 1878757

DOI:: https://doi.org/10.7910/DVN/FSSICO

Citation Formats


                    Schmidtmayr, M., Hughes, J. W., Ryter, F., Wolfrum, E., Cao, N., Creely, A. J., Howard, N., Hubbard, A. E., Lin, Y., Reinke, M. L., Rice, J. E., Tolman, E. A., Wukitch, S., and Ma, Y. Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T.  United States: N. p., 2018. 
        Web.  doi:10.7910/DVN/FSSICO.

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                    Schmidtmayr, M., Hughes, J. W., Ryter, F., Wolfrum, E., Cao, N., Creely, A. J., Howard, N., Hubbard, A. E., Lin, Y., Reinke, M. L., Rice, J. E., Tolman, E. A., Wukitch, S., & Ma, Y. Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T.  United States.  doi:https://doi.org/10.7910/DVN/FSSICO

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                    Schmidtmayr, M., Hughes, J. W., Ryter, F., Wolfrum, E., Cao, N., Creely, A. J., Howard, N., Hubbard, A. E., Lin, Y., Reinke, M. L., Rice, J. E., Tolman, E. A., Wukitch, S., and Ma, Y. 2018.  
"Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T".  United States.  doi:https://doi.org/10.7910/DVN/FSSICO.  https://www.osti.gov/servlets/purl/1878757. Pub date:Thu Oct 04 00:00:00 EDT 2018

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@article{osti_1878757,

  title        = {Investigation of the critical edge ion heat flux for L-H transitions in Alcator C-Mod and its dependence on B_T},

  author       = {Schmidtmayr, M. and Hughes, J. W. and Ryter, F. and Wolfrum, E. and Cao, N. and Creely, A. J. and Howard, N. and Hubbard, A. E. and Lin, Y. and Reinke, M. L. and Rice, J. E. and Tolman, E. A. and Wukitch, S. and Ma, Y.},

  abstractNote = {This paper presents investigations on the role of the edge ion heat flux for transitions from L-mode to H-mode in Alcator C-Mod. Previous results from the ASDEX Upgrade tokamak indicated that a critical value of edge ion heat flux per particle is needed for the transition. Analysis of C-Mod data confirms this result. The edge ion heat flux is indeed found to increase linearly with density at given magnetic field and plasma current. Furthermore, the Alcator C-Mod data indicate that the edge ion heat flux at the L-H transition also increases with magnetic field. Combining the data from Alcator C-Mod and ASDEX Upgrade yields a general expression for the edge ion heat flux at the L-H transition. These results are discussed from the point of view of the possible physics mechanism of the L-H transition. They are also compared to the L-H power threshold scaling and an extrapolation for ITER is given.},

  doi          = {10.7910/DVN/FSSICO},

  journal      = {},

  number       = ,

  volume       = ,

  place        = {United States},

  year         = {Thu Oct 04 00:00:00 EDT 2018},

  month        = {Thu Oct 04 00:00:00 EDT 2018}

}

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DOI: https://doi.org/10.7910/DVN/FSSICO

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