Using field-particle correlations to diagnose wave-particle interactions in laboratory experiments

The recently developed field-particle correlation (FPC) technique [1, 2] provides a valuable new approach to combine single-point measurements of particle velocity distribution functions and electromagnetic fields to identify the kinetic physical mechanisms underlying the collisionless energy transfer between waves and particles and to quantify the resulting rate of change of the microscopic kinetic energy density of the particles in weakly collisional laboratory and astrophysical plasmas. Although the measurement of the particle velocity distribution functions in laboratory plasmas represents a significant technical challenge, the potential for gaining invaluable physical insight from such measurements motivates the development of new diagnostics. Cutting-edge laboratory diagnostics to achieve this goal have been developed based on a number of different approaches: laser induced fluorescence, incoherent Thompson scattering, or wave absorption.