Extreme Particle Acceleration in Shocks: from the laboratory to astrophysics

Introduction

Astrophysical shocks are among the most powerful particle accelerators in the Universe. Generated by violent interactions of supersonic, and often relativistic, plasma flows with the ambient medium, shock waves involve a complex and highly nonlinear interplay between the dynamics of flows, magnetic fields, and accelerated particles through mechanisms not yet fully understood.

Research Questions

Several long-standing scientific questions arise from this field, including:

1. What is the origin of cosmic rays?
2. What controls particle injection and the acceleration efficiency in collisionless shocks?
3. How is the physics of relativistic shocks modified by electron-positron pair production?
4. Can these mechanisms be studied in the laboratory?

These questions are closely tied to extreme plasma physics processes, where the interplay between micro-instabilities and global dynamics is critical.

Technological Advances

Advances in high-power lasers and particle beams are just now opening unique opportunities to probe the microphysics of shocks and particle acceleration in controlled laboratory experiments for the first time. Together with the fast-paced developments in fully-kinetic plasma simulations, computational power, and astronomical observations, the time is ripe to deploy a research program focused on particle acceleration in shocks that can transform our ability to address these questions.

Project Goals

In the ERC grant XPACE, we aim to:

• Use first-principles massively parallel simulations and laboratory experiments to study the microphysics of non-relativistic and relativistic shocks.
• Employ data-driven techniques to develop multi-scale models that bridge the gap between microphysics and global dynamics.

This project will build comprehensive models of the plasma processes that shape magnetic field amplification, particle acceleration, and radiation emission in shocks, with the goal of solving central questions in extreme plasma phenomena. It will also open new avenues between theory, computation, laboratory experiments, and astrophysical observations.