Job Summary

Under general supervision with limited review, this position is responsible for determining and developing effective approaches for resolving a wide range of difficult scientific problems in tokamak impurity transport and pedestal plasma physics relevant to magnetic fusion energy. Assignments are normally outlined in terms of overall objectives and anticipated results. The scientist will document findings, communicate results to scientific staff, and make technical presentations as required.

The scientist may coordinate segments of a specific project. This position performs research within the Comprehensive Investigation of Tokamak Impurities and Understanding of Surfaces (CITIUS) program and the Advancing Intrinsically No-ELM / Small-ELM Regimes for Fusion Pilot Plants (AISER) program, managed by General Atomics on behalf of the U.S. Department of Energy. The scientist will lead experimental interpretation and/or modeling efforts focused on tungsten impurity transport, plasma response to impurity injection, and pedestal transport physics in tokamak plasmas, with emphasis on one or more of the following topics:

• Inference of tungsten core accumulation using coupled transport models and calibrated diagnostics
• Validation of three-dimensional impurity transport models used to predict tungsten erosion and core influx during resonant magnetic perturbations (RMPs)
• Assessment of plasma stability during dust injection to inform sustainable operating regimes
• Quantification of reductions in heat flux and core leakage induced by mid-Z impurity injection during RMP-induced ELM suppression
• Understanding pedestal transport in naturally no-ELM or small-ELM regimes using gyrokinetic simulations
• Optimization of naturally no-ELM or small-ELM regimes for core-edge integration using integrated transport modeling tools

The scientist will collaborate closely with experimental plasma physicists, diagnostic experts, edge and core transport modelers, and external research partners across the CITIUS and AISER teams.

DUTIES AND RESPONSIBILITIES:

The scientist will perform one or more of the following essential functions:

• Lead the planning, execution, analysis, and interpretation of experiments aimed at inferring tungsten core accumulation using coupled edge-core impurity transport models and calibrated diagnostic measurements.
• Apply and validate three-dimensional impurity transport tools to predict tungsten erosion, re-deposition, edge transport, and core influx in plasmas with RMPs.
• Design, execute, and interpret studies of plasma response and stability during dust or particulate injection, including comparison of experimental observations with modeling results to identify sustainable operating boundaries.
• Investigate the effects of mid-Z impurity injection on divertor heat flux, tungsten leakage, and core contamination during RMP-induced ELM suppression using a combination of diagnostics, interpretive analysis, and transport simulations.
• Coordinate with diagnostic teams to integrate measurements from edge, divertor, and core diagnostics into impurity transport analyses and model validation workflows.
• Use coupled impurity transport, edge plasma, and integrated modeling tools to evaluate wall-to-core impurity migration pathways and identify dominant mechanisms governing core contamination.
• Perform gyrokinetic simulations to study pedestal transport in naturally no-ELM and small-ELM regimes and assess the physics mechanisms enabling improved edge performance.
• Apply integrated core-edge transport codes to optimize naturally no-ELM and small-ELM scenarios for improved confinement, impurity control, and reactor-relevant operating performance.
• Prepare technical reports and presentations summarizing methods, results, and impacts; contribute to peer-reviewed publications; and present results at scientific meetings.
• Stay informed about advances in impurity transport modeling, pedestal physics, gyrokinetic simulation, and integrated scenario development, and propose improvements to experimental plans and modeling workflows.
• Perform other duties as assigned or required.

Job Qualifications

• Typically requires a Bachelor's degree, Master's degree or Ph.D. in physics, nuclear engineering, plasma science, or a related scientific/technical field and progressively complex scientific experience as follows: four or more years of experience with a Bachelor's degree and two or more years of experience with a Master's degree. Equivalent scientific experience may be substituted in lieu of education.

Must have:

• A rigorous understanding of scientific concepts, principles, and theory in at least one of the following areas: tokamak edge plasma physics, impurity transport, pedestal physics, plasma stability, or integrated modeling for magnetic fusion.
• Experience demonstrating broad application of those concepts to experimental execution, interpretation, and/or computational modeling problems relevant to fusion plasmas.
• Experience with one or more classes of transport or plasma modeling tools relevant to impurity transport, edge physics, gyrokinetics, or integrated scenario development.

Must possess the ability to:

• Understand new concepts quickly and apply them accurately in an evolving research environment.
• Organize, schedule, and coordinate work phases across experimental campaigns, diagnostic analyses, and modeling tasks.
• Determine the appropriate technical approach at the task level or, with assistance, at the project level to provide solutions to a range of complex problems.

Demonstrated experience in at least two of the following is highly desirable:

• Interpretation of impurity transport experiments in tokamaks using calibrated diagnostics and coupled modeling workflows
• Designing and executing experiments focused on edge plasma physics and impurity transport
• Application of three-dimensional impurity transport codes or related edge/SOL transport tools
• Modeling of tungsten erosion, re-deposition, and/or wall-to-core impurity migration
• Analysis of plasmas with applied RMPs, ELM suppression, and/or impurity seeding
• Studies of plasma response to dust or particulate injection
• Gyrokinetic simulation of pedestal or edge transport using codes such as GENE or CGYRO
• Integrated core-edge transport modeling using codes such as JINTRAC, ASTRA, STEP, or similar tools
• Must have strong communication, computing, documentation, presentation, and interpersonal skills; the ability to work independently and as part of multidisciplinary teams; and the ability to perform complex tasks in one scientific area while interfacing effectively with adjacent disciplines.
• Able to work extended hours and travel as required.
• Original work(s) published in professional scientific journals or formal technical equivalents in relevant areas are highly desirable.