• Validating models for next-generation fu

    From ScienceDaily@1:317/3 to All on Wednesday, April 13, 2022 22:30:46
    Validating models for next-generation fusion facilities

    Date:
    April 13, 2022
    Source:
    DOE/Princeton Plasma Physics Laboratory
    Summary:
    The National Spherical Torus Experiment-Upgrade (NSTX-U) could
    serve as the model for a fusion energy pilot plant.



    FULL STORY ==========================================================================
    The flagship fusion facility of the U.S. Department of Energy's (DOE)
    Princeton Plasma Physics Laboratory (PPPL) could serve as the model for
    an economically attractive next-generation fusion pilot plant, according
    to recent simulations and analysis. The pilot plant could become the next
    U.S. step for harvesting on Earth the fusion power that drives the sun
    and stars as a safe and clean source of power for generating electricity.


    ==========================================================================
    The U.S. fusion community has recently urged an immediate effort to design
    and construct a cost-effective pilot plant to generate electricity in
    the 2040s.

    Unique capabilities of the PPPL flagship, the National Spherical Torus Experiment-Upgrade (NSTX-U) that is currently under repair, have made
    its design a candidate for that role. "It's all about trying to project
    whether this route is favorable for a cost-effective pilot plant and
    beyond," said principal physicist Walter Guttenfelder, lead author of
    a paper in the journal Nuclear Fusion that details the latest findings.

    Fusion produces vast energy by combining light elements such as hydrogen
    in the form of plasma, the hot, charged state of matter composed of free electrons and atomic nuclei, or ions. Plasma composes 99 percent of the
    visible universe and fuels fusion reactions that produce heat and light
    that create and sustain life on Earth.

    The spherically shaped NSTX-U produces high-pressure plasmas required for fusion reactions in a relatively compact and cost-effective configuration.

    Operating capabilities of the facility are greatly enhanced over its pre- upgraded predecessor. "The primary motivation for NSTX-U is to push up to
    even higher powers, higher magnetic fields supporting high-temperature
    plasmas to see if previously observed favorable trends continue,"
    Guttenfelder said.

    Recent theory, analysis and modeling from the NSTX-U research team
    predict that many of these trends should be demonstrated in new NSTX-U experiments.

    Predicted operating conditions for the NSTX-U include the following:
    Starting up plasma. Modeling has been developed to efficiently optimize
    plasma initiation and ramp up, and it was applied to help a spherical
    tokamak facility in the United Kingdom produce its first plasma.



    ========================================================================== Understanding the plasma edge. New models simulate the dynamics between
    the edge of the plasma and the tokamak wall that can determine whether
    the core of the plasma will reach the 150 million-degree temperatures
    needed to produce fusion reactions.

    Applying artificial intelligence.AI machine learning has developed a
    rapid path for optimizing and controlling plasma conditions that closely
    match predicted test targets.

    Novel techniques. Simulations suggest many novel techniques for
    shielding interior NSTX-U components from blasts of exhaust heat from
    fusion reactions.

    Among these concepts is the use of vaporized lithium to reduce the impact
    of heat flux.

    Stable performance. Studies found that a window for NSTX-U performance can remain stable in the face of instabilities that could degrade operations.

    What to avoid. Increased understanding of the conditions to avoid come
    from excellent agreement between the predicted range of unstable plasmas
    and a large experimental data base.

    Considerable progress has therefore been made in understanding and
    projecting how NSTX-U can advance the development of fusion energy,
    the Nuclear Fusionpaper says. "The next step," said Guttenfelder,
    "is to see if new experiments validate what we're predicting, and to
    refine the predictions if not. These steps together will enable more
    confident projections for future devices." Support for this research
    comes from the DOE Office of Science with many simulations produced using resources of the National Energy Research Scientific Computing Center,
    a DOE Office of Science User Facility. Coauthors of the paper include researchers from PPPL and 23 collaborative institutions world-wide.


    ========================================================================== Story Source: Materials provided by
    DOE/Princeton_Plasma_Physics_Laboratory. Original written by John
    Greenwald. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. W. Guttenfelder, D.J. Battaglia, E. Belova, N. Bertelli, M.D. Boyer,
    C.S.

    Chang, A. Diallo, V.N. Duarte, F. Ebrahimi, E.D. Emdee, N. Ferraro,
    E.

    Fredrickson, N.N. Gorelenkov, W. Heidbrink, Z. Ilhan, S.M. Kaye,
    E.-H.

    Kim, A. Kleiner, F. Laggner, M. Lampert, J.B. Lestz, C. Liu,
    D. Liu, T.

    Looby, N. Mandell, R. Maingi, J.R. Myra, S. Munaretto, M. Podesta`,
    T.

    Rafiq, R. Raman, M. Reinke, Y. Ren, J. Ruiz Ruiz, F. Scotti,
    S. Shiraiwa, V. Soukhanovskii, P. Vail, Z.R. Wang, W. Wehner,
    A.E. White, R.B. White, B.J.Q. Woods, J. Yang, S.J. Zweben,
    S. Banerjee, R. Barchfeld, R.E. Bell, J.W. Berkery,
    A. Bhattacharjee, A. Bierwage, G.P. Canal, X. Chen, C.

    Clauser, N. Crocker, C. Domier, T. Evans, M. Francisquez, K. Gan, S.

    Gerhardt, R.J. Goldston, T. Gray, A. Hakim, G. Hammett, S. Jardin,
    R.

    Kaita, B. Koel, E. Kolemen, S.-H. Ku, S. Kubota, B.P. LeBlanc, F.

    Levinton, J.D. Lore, N. Luhmann, R. Lunsford, R. Maqueda,
    J.E. Menard, J.H. Nichols, M. Ono, J.-K. Park, F. Poli, T. Rhodes,
    J. Riquezes, D.

    Russell, S.A. Sabbagh, E. Schuster, D.R. Smith, D. Stotler,
    B. Stratton, K. Tritz, W. Wang, B. Wirth. NSTX-U theory, modeling
    and analysis results. Nuclear Fusion, 2022; 62 (4): 042023 DOI:
    10.1088/1741-4326/ ac5448 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220413091009.htm

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