Relativistic temperature of gas raises the issue of the equation of state (EOS) in relativistic hydrodynamics. We study the EOS for numerical relativistic hydrodynamics, and propose a new EOS that is simple and yet approximates very closely the EOS of the single-component perfect gas in relativistic regime. We also discuss the calculation of primitive variables from conservative ones for the EOSs considered in the paper, and present the eigenstructure of relativistic hydrodynamics for a general EOS, in a way that they can be used to build numerical codes. Tests with a code based on the total variation diminishing (TVD) scheme are presented to highlight the differences induced by different EOSs.

We describe a method for incorporating ambipolar diffusion in the strong coupling approximation into a multidimensional magnetohydrodynamics code based on the total variation diminishing scheme. Contributions from ambipolar diffusion terms are included by explicit finite difference operators in a fully unsplit way, maintaining second order accuracy. The divergence-free condition of magnetic fields is exactly ensured at all times by a flux-interpolated constrained transport scheme. The super time stepping method is used to accelerate the timestep in high resolution calculations and/or in strong ambipolar diffusion. We perform two test problems, the steady-state oblique C-type shocks and the decay of Alfvén waves, confirming the accuracy and robustness of our numerical approach. Results from the simulations of the compressible MHD turbulence with ambipolar diffusion show the flexibility of our method as well as its ability to follow complex MHD flows in the presence of ambipolar diffusion. These simulations show that the dissipation rate of MHD turbulence is strongly affected by the strength of ambipolar diffusion.

Several tricyclic phenoxasilin and phenazasiline heterocycles were synthesized from the corresponding 2,2‘-dilithio-diphenyl ether or diphenyl amine precursor and silicon tetrachloride (or trichlorosilane) followed by reduction with lithium aluminum hydride [H2SiAr2:  Ar2 = C12H8O (1); Ar2 = C14H12O (2); Ar2 = C13H11N (3); Ar2 = C15H15N (4); Ar2 = C13H9Br2N (5)]. The reactivity of hydrosilanes 1−5 with (Ph3P)2Pt(η2-C2H4) (6) was investigated. At room temperature, mononuclear complexes, (Ph3P)2Pt(H)(SiAr2H) and (Ph3P)2Pt(SiAr2H)2, were generally observed by NMR spectroscopy but were too reactive or unstable to isolate. Dinuclear and in some cases trinuclear Pt−Si-containing complexes were observed as the major products from the reactions. Symmetrical dinuclear complexes, [(Ph3P)Pt(μ-η2-H-SiAr2)]2 (8 and 22, respectively), were produced from the reaction of 1 or 3 with 6. In contrast, reaction of silane 2 with 6 produced a trinuclear complex, [(Ph3P)Pt(μ-SiAr2)]3 (16), as the major product. However, reaction of 4 or 5 with complex 6 produced an unsymmetrical dinuclear complex, [(Ph3P)2Pt(H)(μ-SiAr2)(μ-η2-H-SiAr2)Pt(PPh3)] (26 and 30, respectively), as the major component. The molecular structures of a symmetrical (22) and unsymmetrical dinuclear (30) complex as well as a trinuclear (16) complex were determined by X-ray crystallography.

We have studied three-dimensional hydrodynamic interactions of relativistic extragalactic jets with two-phase ambient media. These jets propagate through a denser homogeneous gas and then impact clouds with densities 100 to 1000 times higher than the initial beam density. The deflection angle of the jet is influenced more by the density contrast of the cloud than by the beam Mach number of the jet. A relativistic jet with low relativistic beam Mach number can eventually be slightly bent after it crosses the dense cloud; however, we have not seen permanently bent structures in the interaction of a high relativistic beam Mach number jet with a cloud. The relativistic jet impacts on dense clouds do not necessarily destroy the clouds completely, and much of the cloud body can survive as a coherent blob. This enhancement of cloud durability is partly due to the geometric influence of the off-axis collisions we consider and also arises from the lower rate of cloud fragmentation through the Kelvin-Helmholtz instability for relativistic jets. To compare our simulations with observed extragalactic radio jets, we have computed the approximate surface distributions of synchrotron emission at different viewing angles. These surface intensity maps show relativistic jets interacting with clouds can produce synchrotron emission knots similar to structures observed in many VLBI-scale radio sources. We find that the synchrotron emission increases steeply at the moment of impact and the emission peaks right before the jet passes through the cloud.

MMS3 spacecraft passed the vicinity of the electron diffusion region of magnetotail reconnection on 3 July 2017, observing discrepancies between perpendicular electron bulk velocities and E ! × B ! drift, and agyrotropic electron crescent distributions. Analyzing linear wave dispersions, Burch et al.