In this chapter, we review some features of particle acceleration in astrophysical jets. We begin by describing four observational results relating to the topic, with particular emphasis on jets in active galactic nuclei and parallels between different sources. We then discuss the ways in which particles can be accelerated to high energies in magnetised plasmas, focusing mainly on shock acceleration, second-order Fermi and magnetic reconnection; in the process, we attempt to shed some light on the basic conditions that must be met by any mechanism for the various observational constraints to be satisfied. We describe the limiting factors for the maximum particle energy and briefly discuss multimessenger signals from neutrinos and ultrahigh energy cosmic rays, before describing the journey of jet plasma from jet launch to cocoon with reference to the different acceleration mechanisms. We conclude with some general comments on the future outlook.

中文翻译：

---

天体物理喷流中的粒子加速

在本章中，我们回顾了天体物理喷流中粒子加速的一些特征。我们首先描述与该主题相关的四个观测结果，特别强调活动星系核中的喷流和不同来源之间的平行。然后我们讨论了在磁化等离子体中粒子可以被加速到高能的方式，主要集中在冲击加速、二阶费米和磁重联；在这个过程中，我们试图阐明任何机制必须满足的基本条件才能满足各种观测约束。我们描述了最大粒子能量的限制因素，并简要讨论了来自中微子和超高能宇宙射线的多信使信号，在描述喷射等离子体从喷射发射到茧的旅程之前，参考不同的加速机制。最后，我们对未来前景发表了一些一般性评论。