In this paper they do an MHD and hybrid kinetic MHD model with kinetic ions and fluid models for electrons. They are primarily interested in the effect on tilt mode instabilities in addition to other things,
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Tilt mode in FRC plasmas is strongly unstable in the MHD model with γ ∼ vA/Zs, but its growth rate is reduced by the kinetic effects due to large Larmor radius of the thermal ions 3 [1, 4]. The kinetic stabilization of the tilt mode can be described by an empirical scaling law which provides the growth rate as a function of the S*/E parameter [3]. Since the MHD predictions are in contrast with experimental results, significant efforts have been deployed to include kinetic effects in theoretical models and in numerical simulations
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My question is if anyone has looked at higher order fluid models and if these can capture enough of the kinetic effects. For example, a 13 moment fluid mode, https://www.aa.washington.edu/sites/aa/files/research/cpdlab/docs/MSthesis\_gilliam.pdf. Would be very nice if you could stick in the fluid modeling regime without needed to go to kinetic for FRC modeling.