Space-time structured plasma waves

TL;DR

This paper introduces space-time structured electrostatic plasma waves that can maintain their shape and propagate at arbitrary velocities, independent of plasma conditions, with potential applications in plasma physics and laser-plasma interactions.

Contribution

It demonstrates the creation of linear, propagation-invariant electrostatic wavepackets with customizable velocities and angular momentum, independent of plasma parameters.

Findings

Wavepackets can travel at any group velocity, including backward.

Structured wavepackets maintain localization during propagation.

Wavepackets can be excited by space-time structured laser pulses.

Abstract

Electrostatic waves play a critical role in nearly every branch of plasma physics from fusion to advanced accelerators, to astro, solar, and ionospheric physics. The properties of planar electrostatic waves are fully determined by the plasma conditions, such as density, temperature, ionization state, or details of the distribution functions. Here we demonstrate that electrostatic wavepackets structured with space-time correlations can have properties that are independent of the plasma conditions. For instance, an appropriately structured electrostatic wavepacket can travel at any group velocity, even backward with respect to its phase fronts, while maintaining a localized energy density. These linear, propagation-invariant wavepackets can be constructed with or without orbital angular momentum by superposing natural modes of the plasma and can be ponderomotively excited by space-time structured laser pulses like the flying focus.