The conventional thermal instability criterion can not be applied to the advectiondominated accretion disks around black holes where the radiative cooling is insufficient to balance the viscous heating. The surface density change associated with the temperature perturbations, which was usually neglected in deriving the conventional criterion, was recently shown to be much significant in the adv...

The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an important role in seasonal climate extremes such as...

30 LLE Review, Volume 77 In inertial confinement fusion (ICF) implosions, a laser irradiation induces a shock wave propagating through the target. During the shock transit time, the ablation front travels at a constant velocity, and any surface perturbations could grow due to the Richtmyer-Meshkov (RM)–like instability.1–5 Later, when a rarefaction wave reaches the ablation surface, the acceler...

Prevailing theories on the equatorial Atlantic Niño are based on the dynamical interaction between atmosphere and ocean. However, dynamical coupled ocean-atmosphere models poorly simulate and predict equatorial Atlantic climate variability. Here we use multi-model numerical experiments to show that thermodynamic feedbacks excited by stochastic atmospheric perturbations can generate Atlantic Niñ...

If the surface of a quiescent thin liquid film is suddenly coated by a patch of surface active material like a surfactant monolayer, the film is set in motion and begins spreading. An insoluble surfactant will rapidly attempt to coat the entire surface of the film thereby minimizing the liquid's surface tension. The shear stress that develops during the spreading process produces a maximum in s...

We present numerical calculations of the linearized Navier-Stokes equations for axially extended and axially localized spiral structures in the Taylor-Couette system. The eigenvalue surface for spiral vortices with azimuthal wave number M=2 shows significantly more structure than that for vortices with M=0 and 1. Islands are found in parameter space where axially periodic vortex perturbations c...

Phase perturbations due to inclined surface magnetic field of active region strength are calculated numerically in quiet Sun and simple sunspot models in order to estimate and compare the direct and indirect (thermal) effects of the fields on helioseismic waves. It is found that the largest direct effects occur in highly inclined field characteristic of penumbrae, and scale roughly linearly wit...

Abstract. A family of space-time finite element approximation schemes is presented for the nonlinear partial differential equations governing diffusion in the surface of a body of revolution. The schemes share with the partial differential equations properties ofconservation ofvolume and decrease of area. Numerical experiments are described showing that the result of the linear theory of small ...

In a previous paper, we presented the global solution of a new accretion flow model, namely luminous hot accretion flows (LHAFs). In this Letter, we first show the corresponding thermal equilibrium curve of LHAFs in the mass accretion rate vs. surface density diagram. Then we examine its thermal stability again local perturbations. We find that LHAFs are thermally unstable when thermal conducti...

The purpose of this study was to investigate the contribution of individual muscles (MJRSm) to total joint rotational stiffness (MJRST) about the lumbar spine's L4-5 joint prior to, and following, sudden dynamic flexion or extension perturbations to the trunk. We collected kinematic and surface electromyography (sEMG) data while subjects maintained a kneeling posture on a parallel robotic platf...