Abstract Details
Abstracts
Author: Haley S Wilson
Requested Type: Consider for Invited
Submitted: 2024-03-29 15:20:02
Co-authors: A. O. Nelson, J. McClenaghan, C. Paz-Soldan
Contact Info:
Columbia University
116th St and Broadway Ave
New York, New York 10027
USA
Abstract Text:
Negative triangularity (NT) has shown improved confinement over positive triangularity (PT) L-mode with more desirable power handling characteristics than PT H-mode and thus is an interesting candidate for a tokamak reactor configuration. In this work we scope the performance of an NT reactor-class plasma by levering density and temperature edge boundary conditions, auxiliary power, geometry, magnetic field and current using the transport code TGYRO/TGLF. Two NT fusion pilot plant (FPP) strategies are compared: MANTA, a higher field, smaller major radius concept, and a lower field, larger major radius strategy. Both cases can reach fusion powers over 400 MW with scrape-off layer powers PSOL under 50 MW, enabled by the use of seeded krypton and the absence of a requirement to remain above the L-H power threshold. While triangularity effects are mostly in the edge region, where modeling is difficult, experiment has shown that NT can have density and temperature boundary conditions that are somewhere between that expected in PT L-mode and PT H-mode. We use these boundary conditions to inform reactor-relevant profiles that remain under the pressure gradient limit set by infinite-n ideal ballooning instability. The trade-offs between input power, temperature boundary conditions, and impurities (both seeded and intrinsic) are explored, showing that NT can reach sufficient fusion gain with lower input powers than would be needed for PT L-modes. We find an optimal seeded impurity fraction that balances the need for high fusion power with low PSOL. The dependence of predicted density peaking on particle source location is compared to density peaking scaling law predictions. We show that reactor-relevant particle sources result in low density peaking, but still allow fusion powers sufficient for an FPP. Ultimately, we conclude that both NT FPP strategies can reach fusion performance comparable to PT H-mode FPPs with PSOL low enough to avoid the need for an advanced divertor.
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