Two-fluid and the finite Larmor effects on linear and nonlinear growth of the Rayleigh-Taylor instability in a two-dimensional slab are studied numerically with special attention to high-wave-number dynamics and nonlinear structure formation at a low β-value. The two effects stabilize the unstable high wave number modes for a certain range of the β-value. In nonlinear simulations, the absence of the high wave number modes in the linear stage leads to the formation of the density field structure much larger than that in the single-fluid magnetohydrodynamic simulation, together with a sharp density gradient as well as a large velocity difference. The formation of the sharp velocity difference leads to a subsequent Kelvin-Helmholtz-type instability only when both the two-fluid and finite Larmor radius terms are incorporated, whereas it is not observed otherwise. It is shown that the emergence of the secondary instability can modify the outline of the turbulent structures associated with the primary Rayleigh-Taylor instability.

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Effects of the Hall term and the gyro-viscosity on the Rayleigh-Taylor instability in a 2D rectangular slab are studied numerically. Nonlinear magneto-hydrodynamic (MHD) simulations with these effects reveal that the combination of the Hall term and the gyro-viscosity causes the lower growth rates and the lower saturation level of unstable modes relative those in the single-fluid MHD case, while neither the gyro-viscosity nor the Hall term shows a strong stabilization effect only by itself. It is also shown that the mixing width of the density field can grow as large as that in the single-fluid MHD case, even though the saturation level of the kinetic energy is lowered and the detailed density profile becomes sharper. These numerical results suggest that the extension of the MHD equations can bring about a growth of unstable modes in a lower level, although it does not necessarily mean a weaker impact of the instability to the equilibrium.

J-PARC E07 is the most ambitious and complex emulsion experiment to date investigating double hypernuclei with Hybrid emulsion method. The physics run at the K1.8 beam line in the J-PARC hadron experimental facility have been completed in 2017. The emulsion sheets are presently being analyzed with dedicated optical microscopes. Current statistics are estimated to be more 3 times than that of previous experiments. Quantitative data on the ΛΛ and ΞN interaction are being accumulated successfully via analysis of double Λ and Ξ hypernuclei. Multiple Ξ hypernucleus candidates suggests several features about Ξ hypernucleus that the identification efficiency of 15 Ξ C is significantly higher than other mode, many daughters of 15 Ξ C are identified as He or Be, and multiple bound states of Ξ − exist in the 14 N nucleus. An analysis of X-ray spectroscopy of Ξ − hyperatoms are onging.