Introduction to Plasma Physics: https://arxiv.org/abs/2007.04783

Paul Gibbon

**- что особо ценно - в конце табличка со всеми основными плазменными константами и формулами в СИ и СТС:)**

The following notes are intended to provide a brief primer in plasma physics, introducing common definitions, basic properties and processes typically found in plasmas. These concepts are inherent in contemporary plasma-based accelerator schemes, and thus build foundation for the more advanced lectures which follow in this volume. No prior knowledge of plasma physics is required, but the reader is assumed to be familiar with basic electrodynamics and fluid mechanics.

Comments: 19 pages, contribution to the CAS - CERN Accelerator School: High Gradient Wakefield Accelerators, 11-22 March 2019, Sesimbra, Portugal.

Introduction to Laser Physics: https://arxiv.org/abs/2008.03940

Laura Corner

This paper is a basic introduction to laser physics, especially that relevant to accelerator science. It presents the essential physics of a laser, some of the different types of laser system available, the propagation of laser beams, and the key diagnostics that are used for lasers.

Comments: 12 pages

Introduction to Particle Accelerators and their Limitations: https://arxiv.org/abs/2007.04075

Massimo Ferrario, Bernhard J. Holzer

The paper gives a short overview of the principles of particle accelerators, their historical development and the typical performance limitations. After an introduction to the basic concepts, the main emphasis is to sketch the layout of modern storage rings and their limitations in energy and machine performance. Examples of existing machines - among them clearly the LHC at CERN - demonstrate the basic principles and the technical and physical limits that we face today in the design and operation of these particle colliders. Pushing for ever higher beam energies motivates the design of the future collider studies and beyond that, the development of more efficient acceleration techniques.

Comments: 26 pages

Physics of Laser-Wakefield Accelerators (LWFA): https://arxiv.org/abs/2007.04622

Johannes Wenz, Stefan Karsch

Intense ultrashort laser pulses propagating through an underdense plasma are able to drive relativistic plasma waves, creating accelerating structures with extreme gradients. These structures represent a new type of compact sources for generating ultrarelativistic, ultrashort electron beams. This chapter covers the theoretical background behind the process of LWFA. Starting from the basic description of electromagnetic waves and their interaction with particles, the main aspects of the LWFA are presented. These include the excitation of plasma waves, description of the acceleration phase and injection mechanisms. These considerations are concluded by a discussion of the fundamental limits on the energy gain and scaling laws.

Comments: 31 pages

Particle Beam Diagnostics: https://arxiv.org/abs/2008.05896

Barbara Marchetti

This lecture gives an overview about beam diagnostics techniques for the characterization of electron bunches obtained with plasma accelerators. Due to the limited space, the lecture does not aim to go into the specifics of the single measurements but rather to offer an overview of the present techniques (including ongoing developments) highlighting advantages and disadvantages of each of them. The linked references provide on the other side a more in depth discussion about the technical aspects.

Comments: 13 pages

Acceleration of Electrons in Plasma: https://arxiv.org/abs/2007.03930

A. G. R. Thomas

This is brief review of acceleration of electrons in plasma wakefields driven by either intense laser pulses or particle beams following lectures at the 2019 CERN Accelerator School on plasma accelerators, held at Sesimbra, Portugal. The commonalities between drivers and their strength parameters and operating parameter regimes for current experiments in laser wakefield acceleration (LWFA) and beam driven plasma wakefield acceleration (PWFA) are summarized. Energy limitations are introduced, including the dephasing and depletion lengths for lasers, and the transformer ratio for beam driven plasmas. The concept of the wake Hamiltonian is introduced and the resulting particle orbits are identified in phase space, which illustrates how the peak energy and energy spread of accelerated electrons are determined.

Comments: 19 pages

Injection, Extraction and Matching: https://arxiv.org/abs/2007.04102

Massimo Ferrario

In this paper we introduce, from basic principles, the main concepts of beam focusing and transport of space charge dominated beams in high brightness accelerators using the beam envelope equation as a convenient mathematical tool. Matching conditions suitable for preserving beam quality are derived from the model for significant beam dynamics regimes. The specific case of the plasma accelerator module is also addressed.

Comments: 22 pages

Beam-Driven Systems, Plasma Wakefield Acceleration: https://arxiv.org/abs/2007.05226

Patric Muggli

We expand on the material that was published in the previous Proceedings of the CERN Accelerator School on Plasma Wakefield Acceleration. The material focused on Plasma Wakefield Acceleration in the short, narrow bunch regime. After a brief introduction, we describe Plasma Wakefield Acceleration driven by a bunch train. We then attempt to give simple and intuitive descriptions of bunch self-modulation, occurring when the bunch is long, and of current filamentation, occurring when the bunch is wide. Self-modulation is a means to use existing bunches carrying large amounts of energy to drive plasma wakefields. Current filamentation instability imposes a limitation on how wide a particle bunch can be before transverse break-up may disrupt the wakefields generation and the acceleration process. As in the previous material, we show sample experimental results that demonstrate that much of the physics at play has been observed experimentally.

Comments: 14 pages

Staging of High-Gradient Wakefield Accelerators: https://arxiv.org/abs/2007.05258

C. A. Lindstrøm

Accelerating particles to high energies with a high-gradient wakefield accelerator may require use of multiple stages. Coupling beams from one stage to another can be difficult due to high divergence and non-negligible energy spreads. We review the challenges, technical requirements and currently proposed methods for solving the staging problem.

Comments: 24 pages

Electron Sources from Plasmas: https://arxiv.org/abs/2007.05392

Brigitte Cros

Relativistic electrons are easily generated by self-injection when an intense laser drives a wakefield in a plasma, giving rise to wide electron energy distributions. Several mechanisms involving additional laser beams or different gas composition or distribution can be used to improve the electron beam quality. These mechanisms are introduced and discussed in the perspective of using laser driven electron sources as injectors for plasma accelerators.

Comments: 11 pages

Plasma Sources and Diagnostics: https://arxiv.org/abs/2007.08184

M.J.Garland, J.C.Wood, G.Boyle, J.Osterhoff

Carefully engineered, controlled, and diagnosed plasma sources are a key ingredient in mastering plasma-based particle accelerator technology. This work reviews basic physics concepts, common types of plasma sources, and available diagnostic techniques to provide a starting point for advanced research into this field.

Comments: 24 pages, 14 figures

Simulation of plasma accelerators with the Particle-In-Cell method: https://arxiv.org/abs/2008.07300

J.L.Vay

We present the standard electromagnetic Particle-in-Cell method, starting from the discrete approximation of derivatives on a uniform grid. The application to second-order, centered, finite-difference discretization of the equations of motion and of Maxwells equations is then described in one dimension, followed by two and three dimensions. Various algorithms are presented, for which we discuss the stability and accuracy, introducing and elucidating concepts like numerical stochastic heating, CFL limit and numerical dispersion. The coupling of the particles and field quantities via interpolation at various orders is detailed, together with its implication on energy and momentum conserving. Special topics of relevance to the modeling of plasma accelerators are discussed, such as moving window, optimal Lorentz boosted frame, the numerical Cherenkov instability and its mitigation. Examples of simulations of laser-driven and particle beam-driven accelerators are given, including with mesh refinement. We conclude with a discussion on high-performance computing and a brief outlook.

Comments: 39 pages, 24 figures