Plasma boundary shape control and real-time equilibrium reconstruction on NSTX-U

Boyer, M. ; Battaglia, D. ; Mueller, D. ; Eidietis, N.; Erickson, K. ; Ferron, J.; Gates, D. ; Gerhardt, S. ; Johnson, R.; Kolemen, E. ; Menard, J. ; Myers, C.; Sabbagh, S.; Scotti, F.; Vail, P.
Issue date: 2018
Rights:
Creative Commons Attribution 4.0 International (CC BY)
Cite as:
Boyer, M., Battaglia, D., Mueller, D., Eidietis, N., Erickson, K., Ferron, J., Gates, D., Gerhardt, S., Johnson, R., Kolemen, E., Menard, J., Myers, C., Sabbagh, S., Scotti, F., & Vail, P. (2018). Plasma boundary shape control and real-time equilibrium reconstruction on NSTX-U [Data set]. Princeton Plasma Physics Laboratory, Princeton University. https://doi.org/10.11578/1562092
@electronic{boyer_m_2018,
  author      = {Boyer, M. and
                Battaglia, D. and
                Mueller, D. and
                Eidietis, N. and
                Erickson, K. and
                Ferron, J. and
                Gates, D. and
                Gerhardt, S. and
                Johnson, R. and
                Kolemen, E. and
                Menard, J. and
                Myers, C. and
                Sabbagh, S. and
                Scotti, F. and
                Vail, P.},
  title       = {{Plasma boundary shape control and real-t
                ime equilibrium reconstruction on NSTX-U
                }},
  publisher   = {{Princeton Plasma Physics Laboratory, Pri
                nceton University}},
  year        = 2018,
  url         = {https://doi.org/10.11578/1562092}
}
Description:

The upgrade to the National Spherical Torus eXperiment (NSTX-U) included two main improvements: a larger center-stack, enabling higher toroidal field and longer pulse duration, and the addition of three new tangentially aimed neutral beam sources, which increase available heating and current drive, and allow for flexibility in shaping power, torque, current, and particle deposition profiles. To best use these new capabilities and meet the high-performance operational goals of NSTX-U, major upgrades to the NSTX-U Control System (NCS) hardware and software have been made. Several control algorithms, including those used for real-time equilibrium reconstruction and shape control, have been upgraded to improve and extend plasma control capabilities. As part of the commissioning phase of first plasma operations, the shape control system was tuned to control the boundary in both inner-wall limited and diverted discharges. It has been used to accurately track the requested evolution of the boundary (including the size of the inner gap between the plasma and central solenoid, which is a challenge for the ST configuration), X-point locations, and strike point locations, enabling repeatable discharge evolutions for scenario development and diagnostic commissioning.

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