At the edge of tokamak (and other) plasmas, isolated “blobs” of plasma are often observed, typically moving outwards at a few hundred meters per second. These blobs are elongated along the magnetic field, forming long filaments. These single filaments have a surprisingly complicated range of nonlinear behaviour.

The blob2d model simulates isothermal blobs with a sheath closure, and includes example inputs to get started. This is quite a good place to start learning how to use BOUT++ with a “real” physics model.