First DIII-D-West hybrid scenario similarity experiments for iter-relevant long-pulse operation

Litaudon, Xavier L. [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000169739717); Ding, Siye [General Atomics, San Diego, CA (United States)] (ORCID:0000000219300439); Kim, S. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)]; Lerche, Ernesto A. [Royal Military Academy (Belgium)] (ORCID:0000000345843581); Manas, Pierre [CEA, Saint Paul Lez Durance (France)]; Odstrcil, Tomas [General Atomics, San Diego, CA (United States)] (ORCID:0000000341734230); SGRELLI, Diana [CEA, IRFM, Saint Paul Lez Durance (France)]; Turco, Francesca [General Atomics, San Diego, CA (United States)] (ORCID:0000000237230438); Victor, Brian S. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000212512922); Tema Biwole, Arsene Stephane [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center] (ORCID:0000000247052743); Boyes, William Samuel [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000269304702); Casali, Livia [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000329243674); Cazabonne, Jean Arthur [CEA, Saint Paul Lez Durance (France)] (ORCID:0000000176291375); Gallo, Alberto [Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Cadarache (France)] (ORCID:0000000274727830); Lunsford, Robert [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:0000000335886801); Maget, Patrick [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000287468102); Morales, Jorge [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000231400504); Osborne, Thomas H. [General Atomics, San Diego, CA (United States)] (ORCID:0000000326414597); Park, Jin Myung [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)]; Quadri, Virginia [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0009000733421070); Savoye-Peysson, Yves [CEA, Saint Paul Lez Durance (France)]; Weldon, David [Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Cadarache (France)]; Marinoni, Alessandro [Univ. of California, San Diego, CA (United States)] (ORCID:0000000310045782)

doi:10.1088/1361-6587/ae5adb

DOE OSTI · 3027639

First DIII-D-West hybrid scenario similarity experiments for iter-relevant long-pulse operation

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Abstract

For the first time, similarity experiments between DIII-D and WEST were performed in the ITER "hybrid-like" regime during dedicated campaigns in April and May 2025. The matched parameters include elongation, triangularity, ion ∇B drift direction toward the X-point, qprofile, and core normalized physics quantities in terms of normalized pressure, normalized gyroradius, electron collisionality, ratio of ion to electron temperature, T i /T e . Core transport physics is explored with different aspect ratio (R/a) values (typically 3 at DIII-D and 5 on WEST). DIII-D explored high-beta conditions (electromagnetic effect) with low torque injection (~0 ± 0.5 N•m) using high heating power (up to 6 MW NBI and 2 MW ECRH powers), while scanning the heating mix (ion vs electron), beta, T i /T e , core radiation via controlled tungsten injection using the Laser Blow-Off system. WEST extended operation toward long-duration pulses using its actively cooled tungsten divertor, achieving dominated electron heating regimes with reduced tungsten contamination. Boron impurity injection were scanned on WEST to control edge conditions and core performance. It is found that core confinement improves-manifested by higher electron temperature, total energy content, neutron rate, and ion temperatureunder conditions of low separatrix density, consistent with previous observations [Bourdelle et al., Nucl. Fusion 63 (2023) 056021]. Conditions for Hmode access and for ion heating in electron-dominated regimes in both WEST and DIII-D will be discussed and compared. The ratio of the thermal energy confinement time (τ E ) to the volume-averaged electron-ion collisional heat exchange time (τ e-i ) is a key parameter to enhance ion heating and potentially facilitate H-mode access in electron-heated regimes. These first-of-a-kind coordinated DIII-D and WEST experiments provide a unique multi-machine dataset to validate predictive models and to optimize ITER hybrid-scenario performance under diverse core and edge conditions.

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Litaudon, Xavier L. [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000169739717), Ding, Siye [General Atomics, San Diego, CA (United States)] (ORCID:0000000219300439), Kim, S. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)], Lerche, Ernesto A. [Royal Military Academy (Belgium)] (ORCID:0000000345843581), Manas, Pierre [CEA, Saint Paul Lez Durance (France)], Odstrcil, Tomas [General Atomics, San Diego, CA (United States)] (ORCID:0000000341734230), SGRELLI, Diana [CEA, IRFM, Saint Paul Lez Durance (France)], Turco, Francesca [General Atomics, San Diego, CA (United States)] (ORCID:0000000237230438), Victor, Brian S. [Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)] (ORCID:0000000212512922), Tema Biwole, Arsene Stephane [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center] (ORCID:0000000247052743), Boyes, William Samuel [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)] (ORCID:0000000269304702), Casali, Livia [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0000000329243674), Cazabonne, Jean Arthur [CEA, Saint Paul Lez Durance (France)] (ORCID:0000000176291375), Gallo, Alberto [Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Cadarache (France)] (ORCID:0000000274727830), Lunsford, Robert [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:0000000335886801), Maget, Patrick [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000287468102), Morales, Jorge [CEA, IRFM, Saint Paul Lez Durance (France)] (ORCID:0000000231400504), Osborne, Thomas H. [General Atomics, San Diego, CA (United States)] (ORCID:0000000326414597), Park, Jin Myung [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)], Quadri, Virginia [Univ. of Tennessee, Knoxville, TN (United States)] (ORCID:0009000733421070), Savoye-Peysson, Yves [CEA, Saint Paul Lez Durance (France)], Weldon, David [Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA), Cadarache (France)], Marinoni, Alessandro [Univ. of California, San Diego, CA (United States)] (ORCID:0000000310045782). 2026-04-02. First DIII-D-West hybrid scenario similarity experiments for iter-relevant long-pulse operation. https://doi.org/10.1088/1361-6587%2Fae5adb

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