Burning Plasma Theory

Almost every concept for a fusion power plant requires a burning plasma: one in which the main source of heat for the plasma comes from fusion reactions. Theory and computational modeling play a critical role in understanding the behavior of burning plasma because it is largely inaccessible experimentally. Key areas include:

• How turbulent convection influences heat transport.
• The accumulation and movement of radiating impurities.
• The confinement and dynamics of energetic fusion-born ions.

The Burning Plasma Theory Group is led by Elena Belova.

Discovery Plasma Theory

Plasmas make up 99% of the visible universe, shaping everything from distant galaxies to cutting-edge technologies here on Earth. Beyond fusion energy, plasma physics drives innovation in microelectronics, astrophysics, propulsion technology and more.

Research from the Discovery Plasma Theory Group broadens fundamental plasma theory and translates this deeper understanding so that it can be used to enable innovation in diverse applications.

The Discovery Plasma Theory Group is led by Fatima Ebrahimi.

Edge Plasma Theory

The edge region of fusion plasmas is challenging to model due to steep temperature and density gradients, as well as the interaction between ionized plasma — atoms that have lost or gained electrons, making them electrically charged — and neutral atoms, which carry no charge. This region is crucial for determining plasma performance and setting requirements for plasma-facing components.

We work to advance theoretical and computational capabilities to better understand these processes, enabling us to predict and optimize performance in fusion power plants.

The Edge Plasma Theory Group is led by Felix Parra Diaz.

Equilibrium, Transients and Control Theory

Understanding the equilibrium of magnetically confined plasma is essential for evaluating its stability and ability to retain heat. A plasma is in equilibrium when forces such as magnetic fields and pressure are stable. If the equilibrium is disrupted by large-scale (macroscopic) instabilities, the plasma can rapidly shift to a new equilibrium or, in extreme cases, lose its ability to contain heat entirely — leading to a disruption. These disruptions can cause intense heat to strike reactor walls and generate strong forces on surrounding structures. To make fusion power plants viable, these instabilities must be carefully controlled.

The Equilibrium, Transients and Control Group is led by Nate Ferraro.

Theory Department staff work closely with the National Spherical Torus Experiment-Upgrade (NSTX-U) researchers to develop models that describe the physics of plasmas in NSTX-U and other spherical tokamaks. 

NSTX-U has several characteristics that make it a unique facility for validating plasma theory, including:

• Strong Shaping – An enhanced ability to change plasma's shape allows researchers to study how it can affect stability and confinement.
   
• Small Aspect Ratio – NSTX-U's compact design will determine whether it is the best model for a commercial fusion power plant.
   
• High Plasma Beta – The ratio of plasma pressure to magnetic pressure is high in NSTX-U, making it an ideal test bed for studying pressure-driven effects.
   
• Super-Alfvénic Fast Ions – NSTX-U will provide valuable data on ions traveling faster than the Alfvén speed and how they affect plasma behavior and stability.

The PPPL Theory Department collaborates with private industry to develop and apply advanced theory and modeling capabilities, helping to accelerate the path to commercial fusion energy. These partnerships are typically arranged through programs sponsored by the U.S. Department of Energy, such as the Innovation Network for Fusion Energy and the Advanced Research Projects Agency ‑ Energy, which support research and technology development.

In addition to these programs, direct partnerships through technical service agreements and strategic partnership projects provide additional avenues for collaboration, enabling other institutions to leverage PPPL’s expertise to tackle key challenges in fusion energy development.

Computational modeling is a significant part of our methods and expertise. A key part of this effort is our strong participation in the Scientific Discovery through Advanced Computing (SciDAC) program, where we collaborate with the U.S. Department of Energy's Advanced Scientific Computing Research program to develop and apply high-performance computing techniques to fusion and plasma science. Currently, Theory Department researchers lead two SciDAC-5 projects:

• Computational Evaluation and Design of Actuators for Core-Edge Integration – Led by Felix Parra Diaz, this project focuses on optimizing plasma actuators to improve core-edge integration in fusion devices.
   
• Center for Edge of Tokamak Optimization – Led by Fatima Ebrahimi, this initiative advances computational models to refine edge plasma control in tokamaks.

Learn More about SciDAC