Based on an analysis of a specific electron trajectory in counterpropagating beams, Bell & Kirk (PRL 101, 200403 (2008)) recently suggested that laboratory lasers may shortly be able to produce significant numbers of electronpositron pairs. We confirm their results using an improved treatment of nonlinear Compton scattering in the laser beams. Implementing an algorithm that integrates classical...

BACKGROUND In the European Alps emergency medical helicopter services are regularly involved in avalanche rescue missions. How the helicopter emergency medical system best supports avalanche rescue missions is controversial. AIM OF THE STUDY To study advantages and limitations of the early dispatch of emergency medical helicopters after avalanche accidents. METHODS Data on rescue mission ch...

Certain systems with slow driving and avalanche–like dissipation events are naturally close to a critical point when the ratio of two energy scales is large. The first energy scale is the threshold above which an avalanche is triggered, the second scale is the threshold above which a site is affected by an avalanche. I present results of computer simulations, and a mean–field theory. PACS numbe...

The probability distribution function of the avalanche size in the sandpile model does not verify strict self-similarity under changes of the sandpile size. Here we show the existence of avalanches with different space-time structure, and each type of avalanche has a different scaling with the sandpile size. This is the main cause of the lack of self-similarity of the probability distribution f...

Power estimation and optimization has become a key issue in embedded system design, especially in the rapidly growing market of mobile handheld computing, communication, internet devices that are driven by battery power. It is of paramount importance to estimate and optimize power of those systems during an early design stage at a high level of abstraction in order to efficiently explore the de...

Abstract Some vacuum chambers in particle accelerators perform a waveguide- or resonator-like behavior due to their unique geometries. Electron multipacting caused by such structural property might be able overwhelm the classical beam-induced multipacting. This article shows that wakefields of beams could stimulate resonant modes chamber with near-rectangular waveguide shape and accordingly ind...