Nagoya University · 물리·천문학
이 교수의 연구실은 은하간 매질에서의 별 형성과 분자의 구름 형성 과정을 3차원 자기유체역학 시뮬레이션을 중심으로 연구합니다. 주요 연구 방향은 충격파에 의한 분자구름의 압축, 자기장의 동적 증폭, 그리고 풍성한 불안정성에 의한 구름 형성 메커니즘입니다. 특히 초신성 잔해와 분자구름 간의 상호작용, 충격파에 의한 거대 필라멘트 형성, 자기장의 역할에 중점을 두고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Using three-dimensional magnetohydrodynamics simulations, we investigate general properties of a blast wave shock interacting with interstellar clouds. The shock-cloud interaction generates a turbulent shell through the vorticity generations. In the turbulent shell, the magnetic field is amplified as a result of turbulent dynamo action. In the case of a young supernova remnant, the corresponding strength of the magnetic field is approximately 1 mG. The propagation speed of the shock wave is sign
Abstract Recent observations suggest an that intensive molecular cloud collision can trigger massive star/cluster formation. The most important physical process caused by the collision is a shock compression. In this paper, the influence of a shock wave on the evolution of a molecular cloud is studied numerically by using isothermal magnetohydrodynamics simulations with the effect of self-gravity. Adaptive mesh refinement and sink particle techniques are used to follow the long-time evolution of
Using 3D MHD simulation with the effects of radiative cooling/heating, chemical reactions, and thermal conduction, we investigate the formation of molecular cloud in the ISM. We consider the formation of molecular cloud by accretion of the HI clouds as suggested in recent observations. The simulation shows that the initial HI medium is compressed and piled up behind the shock waves induced by the accretion flows. Since the initial medium is highly inhomogeneous as a consequence of the thermal in
We develop an unconditionally stable numerical method for solving the coupling between two fluids (frictional forces/heatings, ionization, and recombination), and investigate the dynamical condensation process of thermally unstable gas that is provided by the shock waves in a weakly ionized and magnetized interstellar medium by using two-dimensional two-fluid magnetohydrodynamical simulations. If we neglect the effect of magnetic field, it is known that condensation driven by thermal instability
Abstract Recent observations of molecular clouds show that dense filaments are the sites of present-day star formation. Thus, it is necessary to understand the filament formation process because these filaments provide the initial condition for star formation. Theoretical research suggests that shock waves in molecular clouds trigger filament formation. Since several different mechanisms have been proposed for filament formation, the formation mechanism of the observed star-forming filaments req
We report turbulence effects on magnetic reconnection in relativistic plasmas using 3-dimensional relativistic resistive magnetohydrodynamics simulations. We found reconnection rate became independent of the plasma resistivity due to turbulence effects similarly to non-relativistic cases. We also found compressible turbulence effects modified the turbulent reconnection rate predicted in non-relativistic incompressible plasmas; The reconnection rate saturates and even decays as the injected veloc
This study showed the detailed distribution of crystals in C. unshiu peels and their main component was identified using Raman microscopy to be hesperidin for the first time.
Abstract Galactic cosmic rays are believed to be accelerated at supernova remnants. However, whether supernova remnants can be PeV is still very unclear. In this work we argue that PeV cosmic rays can be accelerated during the early phase of a supernova blast-wave expansion in dense red supergiant winds. We solve in spherical geometry a system combining a diffusive–convection equation that treats cosmic-ray dynamics coupled to magnetohydrodynamics to follow gas dynamics. A fast shock expanding i
Abstract Supernova remnants (SNRs) are believed to be the site of galactic cosmic-ray acceleration. However, the details of the cosmic-ray acceleration are still not well understood. Gamma-ray observation is a promising method to study cosmic-ray acceleration in the SNRs, because a hadronic gamma-ray can trace high-energy cosmic-rays above ∼GeV energy. Conventional theory predicts that the hadronic gamma-ray shows a flat νF ν spectrum from the pion-creation threshold energy to the maximum energy