We apply an ad hoc model for dynamical ignition in three-dimensional numerical simulations of thermonuclear supernovae assuming pure deflagrations. The model makes use of the statistical description of temperature fluctuations in the pre-supernova core proposed by Wunsch & Woosley (2004). Randomness in time is implemented by means of a Poisson process. We are able to vary the explosion energy a...

An analysis is presented of ignition, flame spread, and skin burn associated with the ignition and burning of a multilayered jacket. The important physical processes can all be detailed based on simple thermophysical modeling. The ignition process associated with proximity to a radiant heat source is analyzed to see how a change in external (outer) fabric could have diminished the likelihood of...

The paper deals with the assessment of the electrostatic ignition hazards when flammable gases, liquids or powders are handled and processed in industry. It reviews the present state of knowledge in this field based on information available from literature, codes of practice and guidelines. In a short introduction the prerequisites for the ignition of a flammable atmosphere are described. The s...

The ignition process of the catalytic partial oxidation of methane has been studied by diffuse reflectance infrared spectroscopy (DRIFTS) over Pt/Al2O3 catalyst in a freshly reduced (DPt = 1.8 nm), oxidized (DPt = 2.1 nm) and aged (DPt = 5.1 nm) state. The ignition temperature is found to change with the catalyst state following the order oxidized > freshly reduced > aged. Whatever the catalyst...

The formation of ZnSe via a mechanically-induced self-sustaining reaction (MSR) from a Zn/Se mixture showed that only size reduction and mixing of the reactants without product formation occurred during the induction period prior to ignition. Therefore, all mechanical energy supplied by the planetary mill during this time, called the ignition time (tig), was used exclusively in the activation o...

Energy deposition of MeV electrons in dense plasmas, critical for fast ignition in inertial confinement fusion (ICF), is modeled analytically. It is shown that classical stopping and scattering dominate electron transport and energy deposition when the electrons reach the dense plasmas in the cores of compressed targets, while “anomalous” stopping associated with self-generated fields and micro...

The observable properties of a Type Ia supernova are sensitive to how the nuclear runaway ignites in a Chandrasekhar mass white dwarf at a single point at its center, off-center, or at multiple points and times. We present a simple analytic model for the runaway based upon a combination of stellar mixing-length theory and recent advances in understanding RayleighBenard convection. The convectiv...

We present a systematic survey of the capabilities of type Ia supernova explosion models starting from a number of flame seeds distributed around the center of the white dwarf star. To this end we greatly improved the resolution of the numerical simulations in the initial stages. This novel numerical approach facilitates a detailed study of multi-spot ignition scenarios with up to hundreds of i...

As soon as practical, Earth’s low-cost, abundant, environmentally attractive fusion energy resources should be applied to the urgent global challenges of climate change, energy supply, economic growth, and the developing world. A National Ignition Campaign is under way at the recently completed National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) to ignite high-gain...

We investigate the latitude at which type I X-ray bursts are ignited on rapidly rotating accreting neutron stars. We find that, for a wide range of accretion rates Ṁ, ignition occurs preferentially at the equator, in accord with the work of Spitkovsky et al. However, for a range of Ṁ below the critical Ṁ above which bursts cease, ignition occurs preferentially at higher latitudes. The range of ...