Including self-consistent bootstrap currents in the studies of MHD equilibrium and stability becomes important also in recent design activities for advanced stellarators . These MHD calculations require the iteration of 3D equilibrium codes with analytical calculations of the currents. For this kind of MHD calculations and the comparison of the experimentally measured parallel plasma flows with the theoretical calculations, the derivation of reliable analytical formulas and the benchmark tests to clarify their validity in various magnetic configurations are required. In past studies related to the bootstrap currents using the neoclassical transport codes based on the direct calculation of the linearized drift kinetic equations or the Monte Carlo method, quantitative discussions have not yet been done since these codes used the pitch-angle-scattering (or Lorentz) collision operator which does not satisfy the collisional momentum conservation. In analytical derivations of the bootstrap currents in non-symmetric configurations based on so-called moment method in which the collisional momentum conservation is already taken into account, the magnetic configurations are characterized by two kinds of coefficients expressing the parallel viscosity effect, the parallel viscosity coefficients and the geometric factor. Although several analytical formulas for the geometric factor have been proposed and applied to the studies of MHD equilibrium and stability [1-3], the benchmark tests of these formulas by using the numerical calculation codes also have not yet been done by the same reason mentioned above. Especially, the calculation of the geometric factor for the banana regime is complicated, and thus to investigate the geometric factor in the banana regime using the recently developed neoclassical transport calculation method[4] is an important task. In this presentation, we compare the two analytical expressions of the geometric factor given by Shaing, et al.[1] with the numerically obtained geometric factors in various stellarator configurations. It will be shown that formula derived in the Hamada coordinates which reproduces the exact value in the symmetric configurations is more suitable for the quasi-symmetric configurations than that derived in the Boozer coordinates.

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