Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields orga...

A four-dimensional deformable motion algorithm is described for use in the motion compensation of gated cardiac positron emission tomography. The algorithm makes use of temporal continuity and a non-uniform elastic material model to provide improved estimates of heart motion between time frames. Temporal continuity is utilized in two ways. First, incremental motion fields between adjacent time ...

Abstract We propose a computational quantum field theoretical approach to obtain microscopic insight into the creation process of electrons and positrons as well their subsequent motion inside supercritical external with space-time resolution. A machine-learning–based method permits us address fundamental questions such where interaction region particles are being created what initial velocity ...

Novel schemes for generating ultra-low emittance electron beams have been developed in the last years and promise compact particle sources with excellent beam quality suitable future high-energy physics experiments free-electron lasers. Current methods characterization of low such as pepperpot measurements or focus scanning are limited their capability to resolve emittances sub $0.1$ mm mrad re...