About

Hantao Ji is a Professor of Astrophysical Sciences at Princeton University. His research focuses on various areas within astrophysics, including high-energy astrophysics, plasma astrophysics, and space physics. He is associated with the Department of Astrophysical Sciences at Princeton, where he contributes to the academic community through teaching and research. His contact information includes an office phone number and email, and he is affiliated with the Princeton Plasma Physics Laboratory.

Research topics

• Nuclear engineering
• Computational physics
• Nuclear physics
• Physics
• Mechanics
• Engineering
• Materials science
• Mechanical engineering

Selected publications

• DIII-D research to provide solutions for ITER and fusion energy

  Nuclear Fusion · 2024 · 10 citations

  • Nuclear engineering
  • Physics
  • Computational physics

  Abstract The DIII-D tokamak has elucidated crucial physics and developed projectable solutions for ITER and fusion power plants in the key areas of core performance, boundary heat and particle transport, and integrated scenario operation, with closing the core-edge integration knowledge gap being the overarching mission. New experimental validation of high-fidelity, multi-channel, non-linear gyrokinetic turbulent transport models for ITER provides strong confidence it will achieve Q ⩾ 10 operation. Experiments identify options for easing H-mode access in hydrogen, and give new insight into the isotopic dependence of transport and confinement. Analysis of 2,1 islands in unoptimized low-torque IBS demonstration discharges suggests their onset time occurs randomly in the constant β phase, most often triggered by non-linear 3-wave coupling, thus identifying an NTM seeding mechanism to avoid. Pure deuterium SPI for disruption mitigation is shown to provide favorable slow cooling, but poor core assimilation, suggesting paths for improved SPI on ITER. At the boundary, measured neutral density and ionization source fluxes are strongly poloidally asymmetric, implying a 2D treatment is needed to model pedestal fuelling. Detailed measurements of pedestal and SOL quantities and impurity charge state radiation in detached divertors has validated edge fluid modelling and new self-consistent ‘pedestal-to-divertor’ integrated modeling that can be used to optimize reactors. New feedback adaptive ELM control minimizes confinement reduction, and RMP ELM suppression with sustained high core performance was obtained for the first time with the outer strike point in a W-coated, compact and unpumped small-angle slot divertor. Advances have been made in integrated operational scenarios for ITER and power plants. Wide pedestal intrinsically ELM-free QH-modes are produced with more reactor-relevant conditions, Low torque IBS with W-equivalent radiators can exhibit predator-prey oscillations in T e and radiation which need control. High- β P scenarios with q min &gt; 2, q 95 –7.9, β N &gt; 4, β T –3.3% and H 98y2 &gt; 1.5 are sustained with high density ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mi>n</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> = 7E19 m −3 , f G –1) for 6 τ E , improving confidence in steady-state tokamak reactors. Diverted NT plasmas achieve high core performance with a non-ELMing edge, offering a possible highly attractive core-edge integration solution for reactors.

  DOI

• DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy

  Nuclear Fusion · 2021 · 36 citations

  • Physics
  • Nuclear engineering
  • Nuclear physics

  Abstract DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance core and boundary plasmas. Substantial increases in off-axis current drive efficiency from an innovative top launch system for EC power, and in pressure broadening for Alfven eigenmode control from a co-/counter- I p steerable off-axis neutral beam, all improve the prospects for optimization of future long pulse/steady state high performance tokamak operation. Fundamental studies into the modes that drive the evolution of the pedestal pressure profile and electron vs ion heat flux validate predictive models of pedestal recovery after ELMs. Understanding the physics mechanisms of ELM control and density pumpout by 3D magnetic perturbation fields leads to confident predictions for ITER and future devices. Validated modeling of high- Z shattered pellet injection for disruption mitigation, runaway electron dissipation, and techniques for disruption prediction and avoidance including machine learning, give confidence in handling disruptivity for future devices. For the non-nuclear phase of ITER, two actuators are identified to lower the L–H threshold power in hydrogen plasmas. With this physics understanding and suite of capabilities, a high poloidal beta optimized-core scenario with an internal transport barrier that projects nearly to Q = 10 in ITER at ∼8 MA was coupled to a detached divertor, and a near super H-mode optimized-pedestal scenario with co- I p beam injection was coupled to a radiative divertor. The hybrid core scenario was achieved directly, without the need for anomalous current diffusion, using off-axis current drive actuators. Also, a controller to assess proximity to stability limits and regulate β N in the ITER baseline scenario, based on plasma response to probing 3D fields, was demonstrated. Finally, innovative tokamak operation using a negative triangularity shape showed many attractive features for future pilot plant operation.

  DOI

Recent grants

• MRI Consortium: Development of A Large Plasma Device for Studies of Magnetic Reconnection and Related Phenomena

  NSF · $3.1M · 2013–2019

Frequent coauthors

• M. Yamada

  Kanagawa University

  326 shared

• Lan Gao

  Princeton Plasma Physics Laboratory

  187 shared

• Jongsoo Yoo

  175 shared

• W. Fox

  Princeton University

  159 shared

• D. H. Froula

  Energetics (United States)

  154 shared

• Jonathan Jara-Almonte

  Princeton Plasma Physics Laboratory

  113 shared

• Russell M. Kulsrud

  110 shared

• R. D. Petrasso

  Massachusetts Institute of Technology

  103 shared

Labs

• Hantao Ji LaboratoryPI

Education

• Doctor of Science, Physics

  University of Tokyo

  1990

• Master of Science, Physics

  University of Tokyo

  1987

• Bachelor, Physics

  Ehime University

  1985

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