A simple twist makes the two-frequency crab cavity scheme an ideal add-on option to produce picosecond level short pulses in fourth-generation storage rings.

Laser-driven plasma accelerators (LPAs) can generate particle beams with high peak current in a short acceleration distance, making them a promising radiation source in compact setups. However, minimizing beam divergence at the exit of an LPA is crucial for effective beam transport, particularly in free-electron lasers (FELs). The authors implement an integrated plasma lens just a centimeter behind the LPA, effectively collimating the electron beam in a straightforward setup. This technique is essential for generating LPA-driven seeded FELs, and has potential for creating specific density profiles for adiabatic focusing, or for the staging of accelerators.

The judicious shaping of a tube of plasma by one laser enhances the properties of electron bunches accelerated by another.

Probing of electromagnetic fields in high-energy-density experiments is key to understanding questions in fusion processes such as how the fields are compressed, diffuse through the plasma, and can seed instabilities. Many kinetic processes studied, including collisionless shocks, filamentary instabilities, jets, magnetic reconnection, and turbulence, all depend on the field structure. In this review, an overview of experimental techniques and the underpinning theoretical principles and modeling of proton-based imaging is presented, followed by a review of experiments and an outlook for future frontiers in the technique.