Charney-Hasegawa-Mima equation
¥ Ψ –
streamfunction (electrostatic potential).
¥ ρ – Deformation radius (ion
Larmor radius).
¥ β – PV gradient (diamagnetic
drift).
¥ x – east-west (poloidal arc-length)
¥ y – south-north (radial
length).