# Laser Driven Ultra-compact Undulator for Synchrotron Radiation

## TL;DR

This paper introduces a novel laser-driven undulator with a microscopic period and high magnetic field, enabling compact, tunable x-ray sources and potential free electron lasers.

## Contribution

It proposes a new undulator design using a bifilar capacitor-coil target driven by a high-energy laser, achieving ultra-compact size and high magnetic fields.

## Key findings

- Enables generation of tunable 5-250 keV x-rays.
- Achieves strong helical magnetic fields with a few hundred microns period.
- Facilitates development of ultra-compact synchrotron and free electron laser sources.

## Abstract

Laser wakefield accelerators have emerged as a promising candidate for compact synchrotron radiation and even x-ray free electron lasers. Today, to make the electrons emit electromagnetic radiation, the trajectories of laser wakefield accelerated electrons are deflected by transverse wakefield, counter-propagating laser field or external permanent magnet insertion device. Here, we propose a novel type of undulator which has a few hundred microns of period and tens of Tesla of magnetic field. The undulator consists of a bifilar capacitor-coil target which sustains strong discharge current that generates helical magnetic field around the coil axis when irradiated by a high energy laser. Coupling this undulator with state-of-the-art laser wakefield accelerators can, simultaneously, produce ultra-bright quasi-monochromatic x-rays with tunable energy ranging 5-250 keV and optimize the free electron laser parameter and gain length compared with permanent magnet based undulator. This concept may pave a path toward ultra-compact synchrotron radiation and even x-ray free electron lasers.

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Source: https://tomesphere.com/paper/1903.06112