  In a tokamak, trapped electrons subject to a strong electric field cannot run
away immediately, because their parallel velocity does not increase over a
bounce period. However, they do pinch towards the tokamak center. As they pinch
towards the center, the trapping cone becomes more narrow, so eventually they
can be detrapped and run away. When they run away, trapped electrons will have
very a different signature from circulating electrons subject to the Dreicer
mechanism. The characteristics of what are called trapped-electron runaways are
identified and quantified, including their distinguishable perpendicular
velocity spectrum and radial extent.
