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• Available loop voltage and prefill gas pressure for plasma initiation in JA DEMO are clarified. • Conducting shell does not necessarily hinder plasma initiation. • A possible ohmic plasma initiation scenario for JA DEMO is developed. We have investigated ohmic plasma initiation for JA DEMO, a design concept of the tokamak demonstration fusion reactor examined in Japan. A calculation model describing the tokamak plasma initiation phase consisting of the two-dimensional analysis of the coil and eddy currents and the zero-dimensional plasma analysis is developed. It is revealed that the conducting shell does not necessarily hinder plasma initiation, while it provides the stabilizing effect of vertical displacement events. The available loop voltage and prefill gas pressure for initiation in JA DEMO are clarified for developing the initiation scenario. We demonstrate a possible scenario of ohmic plasma initiation, which is consistent with the design specifications of superconducting poloidal field coils. [ABSTRACT FROM AUTHOR]