Parametric study of high-energy ring-shaped electron beams from a laser wakefield accelerator

Abstract: Laser wakefield accelerators commonly produce on-axis, low-divergence, high-energy electron beams. However, a high charge, annular shaped beam can be trapped outside the bubble and accelerated to high energies. Here we present a parametric study on the production of low-energy-spread, ultra-relativistic electron ring beams in a two-stage gas cell. Ring-shaped beams with energies higher than 750 MeV are observed simultaneously with on axis, continuously injected electrons. Often multiple ring shaped beams with different energies are produced and parametric studies to control the generation and properties of these structures were conducted. Particle tracking and particle-in-cell simulations are used to determine properties of these beams and investigate how they are formed and trapped outside the bubble by the wake produced by on-axis injected electrons. These unusual femtosecond duration, high-charge, high-energy, ring electron beams may find use in beam driven plasma wakefield accelerators and radiation sources

Mitochondrion-Related Organelles in Free-Living Protists

Editor: Jan Tachezy: Series Editor: Alexander Steinbüchel.-- First Online: 10 August 2019.Mitochondrion-related organelles (MROs) are organelles that have independently evolved from mitochondria in eukaryotes that live in low-oxygen conditions. These organelles are functionally diverse, possessing a range of ancestrally mitochondrial or horizontally acquired biochemical pathways. Early studies of MROs focused mainly on parasitic organisms; however, the past decade has seen a growing body of work on the MROs of free-living eukaryotes based on comparative genomics, making it possible to tease apart adaptations to low-oxygen conditions from adaptations to parasitism. Here, we review current knowledge of MROs in free-living eukaryotes.Peer reviewe