Inverse-dee- and square-shaped equilibria are observed by experimentally mapping the magnetic-flux plot as a function of time in a tokamak with a 4-null poloidal divertor. Inverse-dee equilibria are observed to be unstable to the vertical magnetohydrodynamic axisymmetric instability on a time scale ∼1000 poloidal Alfvén times. Square equilibria are stable on the time scale available for observation. Instability growth is apparently slowed by field-shaping hoop and wall passive stabilization.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)