# Particle Acceleration in Pulsar Wind Nebulae: PIC modelling

## TL;DR

This paper reviews how particle-in-cell simulations help understand particle origins and acceleration mechanisms in pulsar wind nebulae, emphasizing magnetic reconnection's role alongside Fermi processes in explaining observed emissions.

## Contribution

It highlights the importance of PIC simulations in revealing magnetic reconnection as a key particle acceleration process in PWNe.

## Key findings

- Magnetic reconnection significantly contributes to particle acceleration in PWNe.
- PIC simulations support a combined acceleration scenario involving Fermi processes and reconnection.
- Reconnection processes explain multi-wavelength emission features of the Crab Nebula.

## Abstract

We discuss the role of particle-in-cell (PIC) simulations in unveiling the origin of the emitting particles in PWNe. After describing the basics of the PIC technique, we summarize its implications for the quiescent and the flaring emission of the Crab Nebula, as a prototype of PWNe. A consensus seems to be emerging that, in addition to the standard scenario of particle acceleration via the Fermi process at the termination shock of the pulsar wind, magnetic reconnection in the wind, at the termination shock and in the Nebula plays a major role in powering the multi-wavelength signatures of PWNe.