In this paper the zero reaction limit of the hyperbolic conservation law with stiff source term of monostable type ∂tu+ ∂xf(u) = 1 u(1− u) is studied. Solutions of Cauchy problems of the above equation with initial value 0 ≤ u0(x) ≤ 1 are proved to converge, as → 0, to piecewise constant functions. The constants are separated by either shocks determined by the Rankine-Hugoniot jump condition, o...

The motions of relativistic particles in a magnetosonic shock wave propagating obliquely to an external magnetic field are studied. In the zeroth-order theory, particles continue to move nearly parallel to the external magnetic field in the shock transition region, when the shock speed is close to c cos θ, where c is the speed of light and θ is the propagation angle. Perturbations to this zerot...

A new instability mechanism is described in accretion flows where the gas is accelerated from a stationary shock to a sonic surface. The instability is based on a cycle of acoustic and entropic waves in this subsonic region of the flow. When advected adiabatically inward, entropy perturbations trigger acoustic waves propagating outward. If a shock is present at the outer boundary, acoustic wave...

This paper presents an optimized low-dissipation monotonicity-preserving (MPLD) scheme for numerical simulations of high-speed turbulent flows with shock waves. By using the bandwidth dissipation optimization method (BDOM), the linear dissipation of the original MP scheme of Suresh and Huynh (J. Comput. Phys. 136, 83–99, 1997) is significantly reduced in the newly developed MP-LD scheme. Meanwh...

CIZA J2242.8+5301 is a post-core passage, binary merging cluster that hosts a large, thin, arc-like radio relic, nicknamed the ‘Sausage’, tracing a relatively strong shock front. We perform spatially-resolved spectral fitting to the available radio data for this radio relic, using a variety of spectral ageing models, with the aim of finding a consistent set of parameters for the shock and radio...

Using a 1-D numerical hydrodynamic model, the evaporation shock evolution is computed in the solar atmosphere having the density profile derived from radioastronomical observations. Then the optical thickness of the 1-4.5 GHz plasma emission on harmonic frequency is computed. It is found that the optical thickness of the radio emission is reduced at the evaporation shock. With a motion of this ...