Advancing fusion energy through precise plasma edge control.
ORNL’s Power Exhaust and Particle Control (PEPC) group is developing technologies to control plasma behavior and manage extreme conditions at the edge of fusion plasmas.
Controlling the edge of fusion plasmas is one of the biggest challenges to making fusion energy a reality.
Achieving this control requires managing the extreme heat and particle fluxes within test reactors and understanding of how the outer edge of fusion plasma—the boundary—interacts with the fusion chamber and with the core plasma.
The PEPC group is enabling the precise control of plasma behavior by performing experiments to validate computational models, innovating new methods to sense and control plasma conditions, and developing plasma-facing components to support the operation of future fusion energy systems.
Integrating theory, simulation, and experimentation
Effective power exhaust safely manages the intense heat generated during fusion reactions, while particle control ensures that plasma purity is maintained and reactor components are protected from erosion and degradation. The PEPC group employs a wide range of skills and technologies to meet these research and design needs, including core technical capabilities such as:
- Plasma boundary simulation: Accurately model plasma-material interactions, heat fluxes, and particle transport at the plasma boundary using state-of-the-art simulation capabilities using boundary simulation tools such as SOLPS-ITER and EMC3-EIRENE.
- Synthetic edge diagnostics: Developing innovative diagnostic tools and advanced data interpretation methods to validate theoretical models under realistic fusion conditions.
- Real-time, model-based control methods: Creating robust, time-dependent control strategies using advanced sensors and predictive modeling to ensure stable and efficient plasma core and boundary conditions.
- Integrated plasma-facing component engineering: Prototyping advanced plasma-facing components for experiments on real-world linear and toroidal plasma confinement devices.
Global collaboration for fusion readiness
The PEPC group is partnered with leading public and private fusion research organizations, including work on international tokamak and stellarator facilities such as:
- DIII-D: The PEPC team leads experiments on detachment control, core-edge integration, and plasma-material interactions. The team also aids in the design of divertor, baffle and limiter systems to inform upgrades to plasma facing components.
- SPARC: The team has informed the design of actuators and diagnostics for exhaust control while using integrated predictive modeling and multi-device experimental analysis to develop control-room ready strategies for power exhaust and core-edge integration.
- WEST: The group deployed fast filterscopes and high-resolution spectrometers to capture transient and steady-state exhaust dynamics, coupling measurements to predictive modeling and synthetic diagnostics. Ongoing collaborations will inform materials choices and exhaust control strategies for next-step fusion devices.
- MAST-U: PEPC personnel are integrated with the MAST-U tea, operating and performing analysis for bolometric and spectroscopic diagnostics, leading experiments, performing predictive and interpretive modeling, and working to advance the physics basis for a low aspect ratio fusion pilot plant.
- W7-X: PEPC researchers are participating in experiments on particle control, measurements of gas output and helium transport modelling, as well as enhancing filtered plasma emission diagnostics in support of broader W7-X physics goals.
- ST40: ORNL scientists and engineers are collaborating with Tokamak Energy staff to better understand low-recycling plasmas in ST40 using lithium wall conditioning. The PEPC team is integrating core fueling in ST40 by installing a multi-barrel pellet injection system to eliminate the need for edge gas fueling for low recycling plasmas. The team is also working to understand lithium sourcing and transport into the core plasma using diverter and core spectroscopy diagnostics as well as the IPS-FASTRAN code suite and understand the unique exhaust physics in this plasma scenario using dual-band IR Thermography.
Through these collaborations, PEPC makes critical contributions to power exhaust and particle control research, from divertor optimization to advanced diagnostics and innovative boundary control methods.
Toward practical fusion energy systems.
The PEPC group represents a unique expertise in fusion energy efficiency, pulse duration, energy storage, and plasma confinement. Their research is establishing the engineering and scientific groundwork needed for reliable, day-one operation of future fusion pilot plants.