Gyrokinetic analysis of global high-beta MHD eqiulibria*

To build high power density, compact, fusion devices one possibility is to use very high beta equilibria. These have previously been studied in the context of MHD stability (Hsu, Artun and Cowley PoP 3,266 (1996)). We wish to look at their transport and confinement properties. To this end, we present a linear gyrokinetic stability analysis of high-beta, up-down-symmetric, global MHD equilibria. These equilibria were obtained using the asymptotic methods of Hsu et al. We investigate the effects of the five good properties of these equilibria mentioned by Hsu et al: reduced trapped particle fraction, strongly stabilising average curvature, short connection lengths in the bad curvature region, intense local magnetic shear and locally-favourable grad-B drifts.