Pegasus Toroidal Experiment


Pegasus Toroidal Experiment
Pegasus Toroidal Experiment (6140926094).jpg
Device typeSpherical tokamak
LocationMadison, Wisconsin, US
AffiliationUniversity of Wisconsin–Madison
Technical specifications
Major radius45 cm (18 in)
Minor radius40 cm (16 in)
WebsitePegasus Toroidal Experiment webpage

The Pegasus Toroidal Experiment is a plasma confinement experiment relevant to fusion power production, run by the Department of Engineering Physics of the University of Wisconsin–Madison. It is a spherical tokamak, a very low-aspect-ratio version of the tokamak configuration, i.e. the minor radius of the torus is comparable to the major radius.

Local Helicity Injection

Pegasus is used to study start up of spherical tokamaks using local helicity injection.[1][2]


Pegasus is being upgraded in 2019 (eg. by removal of the central solenoid) to build the Unified Reduced Non-Inductive Assessment (URANIA) experiment. This will study plasma startup using transient coaxial helicity injection (CHI).[2][1]

The max toroidal field is being increased from 0.15 T to 0.6 T, and the pulse duration from 25 to 100 ms.[3]


  1. ^ a b Advancing Local Helicity Injection for Non-Solenoidal Tokamak Startup Bongard 2018
  2. ^ a b URANIA: A Dedicated Spherical Tokamak Experiment for Developing Non-Solenoidal Plasma Startup Techniques
  3. ^ Research Directions on the Pegasus Toroidal Experiment Reusch 2018