Electron acceleration by a wavy shock front: details on angular distribution

On “box” models of shock acceleration and electron synchrotron spectra

The recent detection of high energy γ-rays coming from supernova remnants and active galactic nuclei has revived interest in the diffusive shock acceleration of electrons. In the present paper we examine the basis of the so-called “box” model for particle acceleration and present a more physical version of it. Using this we determine simple criteria for the conditions under which “pile-ups” can...

Shock front nonstationarity and ion acceleration in supercritical perpendicular shocks

Photon angular distribution in nuclear excitation by electron capture

In the resonant process of nuclear excitation by electron capture (NEEC), a free electron is captured into a bound atomic shell with the simultaneous excitation of the nucleus. NEEC is a process analogous to dielectronic recombination (DR), and when followed by the radiative decay of the nucleus, it is a competing resonant channel of radiative recombination (RR). Partly due to the dominant RR b...

Electron Acceleration at a Low-mach-number Perpendicular Collisionless Shock

A full particle simulation study is carried out on the electron acceleration at a collisionless, relatively low Alfven Mach number (MA = 5), perpendicular shock. Recent self-consistent hybrid shock simulations have demonstrated that the shock front of perpendicular shocks has a dynamic rippled character along the shock surface of low-Mach-number perpendicular shocks. In this paper, the effect o...

Unveiling the orbital angular momentum and acceleration of electron beams.

New forms of electron beams have been intensively investigated recently, including vortex beams carrying orbital angular momentum, as well as Airy beams propagating along a parabolic trajectory. Their traits may be harnessed for applications in materials science, electron microscopy, and interferometry, and so it is important to measure their properties with ease. Here, we show how one may imme...