# Studies of a Terawatt X-Ray Free-Electron Laser

## TL;DR

This paper explores the conditions for achieving terawatt-level x-ray free-electron lasers using simulations, emphasizing the importance of extreme electron beam focusing and various undulator configurations to reach over 1 TW power levels.

## Contribution

It demonstrates that extreme transverse electron beam focusing is crucial for TW x-ray FELs and compares different undulator and focusing configurations through simulations.

## Key findings

- Extreme focusing of the electron beam is essential for TW power levels.
- Strong focusing FODO lattices outperform natural weak focusing in achieving high power.
- Pure SASE and self-seeding can reach TW powers with proper focusing.

## Abstract

The possibility of constructing terawatt (TW) x-ray free-electron lasers (FELs) has been discussed using novel superconducting helical undulators [5]. In this paper, we consider the conditions necessary for achieving powers in excess of 1 TW in a 1.5 {\AA} FEL using simulations with the MINERVA simulation code [7]. Steady-state simulations have been conducted using a variety of undulator and focusing configurations. In particular, strong focusing using FODO lattices is compared with the natural, weak focusing inherent in helical undulators. It is found that the most important requirement to reach TW powers is extreme transverse compression of the electron beam in a strong FODO lattice. The importance of extreme focusing of the electron beam in the production of TW power levels means that the undulator is not the prime driver for a TW FEL, and simulations are also described using planar undulators that reach near-TW power levels. In addition, TW power levels can be reached using pure self-amplified spontaneous emission (SASE) or with novel self-seeding configurations when such extreme focusing of the electron beam is applied.

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Source: https://tomesphere.com/paper/1706.03051