computations of the blowout phase itself, and the possibility and limitations of quantitative comparison to experiment. The gyrofluid model used herein is given in Ref. [29]. It is based on the original derivations given in Refs. [33, 34], with corrections given as motivated by free energy conservation. An alternative derivation using the conservation laws of the underlying gyrokinetic model is given in Ref. [35]. The equations are normalised to spatial scale a and time scale a/c$_{s}$ where a is the minor radius and c$_{s}$ is the reference sound speed given by c 2 s = T$_{e}$/M$_{i}$ , that is, in terms of the electron temperature (in energy units) and ion mass. The main parameters are the drift parameter, electron dynamical beta, and electron collisionality, respectively given by where c and e are the speed of light and fundamental charge, p$_{e}$ and τ$_{e}$ are the pressure and Braginskii collision time [36] of the electrons, and ρ$_{s}$ = c$_{s}$M$_{i}$c/eB is the drift scale. Note that if T$_{i}$ = T$_{e}$ then ρ$_{s}$ = ρ$_{i}$ . The reference for M$_{i}$ is the deuterium mass M$_{D}$ . For the electrons the physical value of the mass m$_{e}$/M$_{D}$ = 1 / 3670 is always used. With global geometry there is no single magnetic field line connection length, but one with a profile with 2 πqR 0 a function of the minor radius coordinate, where R 0 is a constant giving the reference value of the major radius. Each species z has its own set of gyrofluid moment variable equations, one each for density ˜ n$_{z}$ , parallel velocity ˜ u$_{z}$$_{‖}$ , parallel and perpendicular temperature ˜ T$_{z}$$_{‖}$ and ˜ T$_{z}$$_{⊥}$ , and parallel and perpendicular energy components of the parallel heat flux ˜ q$_{z}$$_{‖}$ and ˜ q$_{z}$$_{⊥}$ . They are coupled to the electrostatic and parallel magnetic potentials ˜ φ and A$_{‖}$ through self consistent field equations. The tilde denotes a dependent variable to distinguish from constant parameters. The correspondence of these equations to the Braginskii fluid model is given in Ref. [30]. Each species is characterised by a background charge density, temperature/charge ratio, and II. THE GYROFLUID MODEL WITH RADIALLY DEPENDENT AXISYMMET- RIC GEOMETRY ρ$_{∗}$ = ρ$_{s}$ a β$_{e}$ = 4 πp$_{e}$ B 2 ν$_{e}$ = a c$_{s}$τ$_{e}$ (1) A. Species constants and gyrofluid moment equations 5