Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

Lunsford, R. ; Sun, Z.; Maingi, R. ; Hu, J. S.; Mansfield, D. ; Xu, W.; Zuo, G. Z.; Diallo, A. ; Osborne, T.; Tritz, K.; Canik, J.; Huang, M.; Meng, X. C.; Gong, X. Z.; Wan, B. N.; Li, J. G.
Issue date: 2017
Rights:
Creative Commons Attribution 4.0 International (CC BY)
Cite as:
Lunsford, R., Sun, Z., Maingi, R., Hu, J. S., Mansfield, D., Xu, W., Zuo, G. Z., Diallo, A., Osborne, T., Tritz, K., Canik, J., Huang, M., Meng, X. C., Gong, X. Z., Wan, B. N., & Li, J. G. (2017). Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST [Data set]. Princeton Plasma Physics Laboratory, Princeton University. https://doi.org/10.11578/1562089
@electronic{lunsford_r_2017,
  author      = {Lunsford, R. and
                Sun, Z. and
                Maingi, R. and
                Hu, J. S. and
                Mansfield, D. and
                Xu, W. and
                Zuo, G. Z. and
                Diallo, A. and
                Osborne, T. and
                Tritz, K. and
                Canik, J. and
                Huang, M. and
                Meng, X. C. and
                Gong, X. Z. and
                Wan, B. N. and
                Li, J. G.},
  title       = {{Injected mass deposition thresholds for
                lithium granule instigated triggering of
                 edge localized modes on EAST}},
  publisher   = {{Princeton Plasma Physics Laboratory, Pri
                nceton University}},
  year        = 2017,
  url         = {https://doi.org/10.11578/1562089}
}
Description:

The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. It was also demonstrated that below 600 microns the triggering efficiency decreased roughly with granule size. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper single null discharges with an ITER like tungsten monoblock divertor. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. For those granules of sufficient size, ELM triggering was a prompt response to granule injection. By simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined.

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