Edge Pedestal

A signature feature of high confinement (H-mode) tokamak plasmas is the formation of an edge pedestal region in which steep gradients in the density and temperature and wells in the radial electric field and rotation velocity are observed.  The structure of and transport in this edge pedestal has been a focus of collaborative research involving Georgia Tech and General Atomics members of the National DIII-D Team.


Stacey, W. M.  “A Composite Neoclassical Toroidal Viscosity Model Incorporating Torques from both Axisymmetric and Nonaxisymmetric Tokamak Magnetic Fields”, Fusion Science and Technology (2018) , DOI: 10.1080/15361055.2018.1506626

Stacey, W. M. “Particle, Momentum, and Energy Conserving Fluid Transport Theory for the Tokamak Plasma Edge” Georgia Institute of Technology. (2018).


Stacey, W. M. “Georgia Tech Ion Orbit Loss (IOL) Model” Georgia Institute of Technology. (2017).

Stacey, W. M. “Extended fluid transport theory in the tokamak plasma edge.” Nuclear Fusion 57.6 (2017): 066034.

Wilks, T. M., W. M. Stacey, and T. E. Evans. “Calculation of the radial electric field from a modified Ohm’s law.” Physics of Plasmas 24.1 (2017): 012505.


T. Wilks and W. M. Stacey. “Improvements to an ion orbit loss calculation in the tokamak edge.” Phys. Plasmas 23, 122505 (2016)

Stacey, W. M. “A fluid model for the edge pressure pedestal height and width in tokamaks based on the transport constraint of particle, energy, and momentum balance.” Physics of Plasmas 23.6 (2016): 062515

Stacey, W. M. “Recent Developments in Plasma Edge Theory.” Contributions to Plasma Physics 56.6‐8 (2016): 495-503.

Stacey, W. M., and T. M. Wilks. “Inclusion of ion orbit loss and intrinsic rotation in plasma fluid rotation theory.” Physics of Plasmas 23.1 (2016): 012508.


W.M. Stacey. “White paper for DOE-OFES integrated simulation boundary (B) workshop.” April, 10, 2015.

W. M. Stacey and M.T. Schumman. “The distribution of ion orbit loss fluxes of ions and energy from the plasma edge across the last closed flux surface into the scrape-off layer”. Phys. Plasmas 22, 042504 (2015).

J.-P. Floyd, W. M. Stacey, R. J. Groebner, and S.C. Mellard. “Evolution of edge transport between edge-localized modes in DIII-D”. Phys. Plasmas 22, 022508 (2015).


W. M. Stacey. “Extension of Ion Orbit Loss Theory”. Phys. Plasmas 21, 014502 (2014).

W. M. Stacey. “Sensitivity of the interpretation of the experimental ion thermal diffusivity to the determination of the ion conductive heat flux”. Phys. Plasmas 21, 042508 (2014).

W. M. Stacey. “Structure in the edge plasma profiles in tokamaks.”Contrib. Plasma Phys. 54, No. 4-6, 524-528 (2014)


W. M. Stacey. “Interpretation of Diffusive and Non-Diffusive Transport in Tokamak Edge Pedestal Measurements”.Fusion Sci. Technol. 61 34 (2013).

W. M. Stacey, M.-H. Sayer, J.-P. Floyd, and R. J. Groebner. “Interpretation of Changes in Diffusive and Non-Diffusive Transport in the Edge Pedestal During Pedestal Buildup Following a Low-High Transition in DIII-D”. Phys. Plasmas 20, 012509 (2013).

W. M. Stacey. “Effect of Ion Orbit Loss on Distribution of Particle, Energy, and Momentum Sources into the Tokamak Scrape-Off Layer”. Nuclear Fusion 53 063011 (2013).

T. M. Wilks, W. M. Stacey, and T. E. Evans. “Analysis of Toroidal Phasing of Resonant Magnetic Perturbation Effects on Edge Transport in the DIII-D Tokamak”. Phys. Plasmas 20 052505 (2013).

W. M. Stacey. “Effect of Ion Orbit Loss on the Structure in the H-Mode Tokamak Edge Pedestal Profiles of Rotation Velocity, Radial Electric Field, Density, and Temperature”. Phys. Plasmas 20 092508 (2013).


W. M. Stacey, R. J. Groebner, and T. E. Evans. “Non-Diffusive Transport in the Tokamak Edge Pedestal”. Nucl. Fusion 52, 114020 (2012).

W. M. Stacey. “Suggested DIII-D Research Focus on Pedestal/Boundary Physics”. DIII-D Planning Meeting, January 26, 2012.

J.-P. Floyd and W. M. Stacey. “Numerical Investigation of Extending Diffusion Theory Codes to Solve the Generalized Pinch-Diffusion Equations in the Edge Pedestal”. Fusion Sci. Technol. 61 227-235 (2012).


W. M. Stacey and T. E. Evans, “The Role of Radial Particle Pinches in ELM Suppression by Resonant Magnetic Perturbations”, Nucl. Fusion 51, 013007 (2011).

W. M. Stacey and R. J. Groebner, “Evolution of the H-mode Edge Pedestal Between ELMS”. Nucl. Fusion 51063024 (2011).

W. M. Stacey. “The Effect of Ion Orbit Loss and X-Loss on the Interpretation of Ion Energy and Particle Transport in the DIII-D Edge Plasma”. Phys. Plasmas 18, 102504 (2011).


W. M. Stacey, “The Effect of Rotation and Viscous Heating on the Interpretation of Experimental Heat Diffusivities in the Edge Pedestal”, Phys. Plasmas 17, 052504 (2010).

W. M. Stacey, “The Effects of Rotation, Electric Field, and Recycling Neutrals on Determining the Edge Pedestal Density Profile”, Phys. Plasmas 17, 052506 (2010).

W. M. Stacey and R. J. Groebner, “Force Balance and Ion Particle Transport Differences in High and Low Confinement Tokamak Edge Pedestals”, Phys. Plasmas 17, 112512 (2010).

J. D. Callen, et al., W. M. Stacey, “Analysis of Pedestal Transport”, Nucl. Fusion 50, 064004 (2010).


W. M. Stacey and R. J. Groebner, “Interpretation of Particle Pinches and Diffusion Coefficients in the Edge Pedestal of DIII-D H-Mode Plasmas”, Phys. Plasmas 16, 102504 (2009).


W. M. Stacey, “Comparison of Theoretical and Experimental Heat Diffusivities in the DIII-D Edge Plasma”, Phys. Plasmas 15, 052503 (2008).


118897_L_H_mode_thermal_inferrence__summer_06W. M. Stacey and R. J. Groebner, “Thermal transport analysis of the edge region in the low and high confinement stages of a DIII-D discharge”, Phys. Plasmas 14, 012501 (2007).paper

W. M. Stacey and R. J. Groebner, “Experimentally inferred thermal diffusivities in the edge pedestal between edge-localized modes in DIII-D”, Phys. Plasmas 14, 122504 (2007).


W. M. Stacey and R. J. Groebner, “Investigation of edge pedestal structure in DIII-D”, Phys. Plasmas 13, 012513 (2006).

W. M. Stacey and R. J. Groebner, “Thermal Transport in the DIII-D Edge Pedestal”, Phys. Plasmas 13, 072510 (2006).

W. M. Stacey and T. E. Evans, “Investigation of background edge thermal transport in ELMing and ELM-suppressed H-modes in DIII-D”, Phys. Plasmas 13, 112506 (2006).


W. M. Stacey and R. J. Groebner, “Application of a particle, momentum, and energy balance model to calculate the structure of the edge pedestal in DIII-D”, Phys. Plasmas 12, 042504 (2005).


W. M. Stacey, “Investigation of transport in the DIII-D edge pedestal”, Phys. Plasmas 11, 1511 (2004).

W. M. Stacey, “Structure of the edge density pedestal in tokamaks”, Phys. Plasmas 11, 4295 (2004).

W. M. Stacey, “Edge pedestal structure”, Phys. Plasmas 11, 5487 (2004).


W. M. Stacey and R. J. Groebner, “A framework for the development and testing of an edge pedestal model: Formulation and initial comparison with DIII-D data”, Phys. Plasmas 10, 2412 (2003).


W. M. Stacey, “An Edge Pedestal Model”, Contrib. Plasma Phys. 42, 283 (2002).

W. M. Stacey, “An edge pedestal investigation for high-confinement tokamak plasmas”, Phys. Plasmas 9, 1332 (2002).


W. M. Stacey, “An edge pedestal model based on transport and atomic physics”, Phys. Plasmas 8, 4073 (2001).