The Field-Particle Correlation Technique: A Nonlinear Method for Determining Particle Energization in Space Plasmas

Understanding the removal of energy from turbulent fluctuations in a
magnetized plasma and the consequent energization of the constituent
plasma particles is a major goal of heliophysics. Under the weakly
collisional conditions typical of the solar wind plasma, kinetic
theory dictates that the energy of turbulent fluctuations of the
electromagnetic fields and plasma flows is removed collisionlessly
through inherently nonlinear interactions between the electromagnetic
fields and the individual motions of the charged particles that make
up the plasma. We present the fundamentals of the recently developed
field-particle correlation technique, and show examples from nonlinear
kinetic numerical simulations of how it can be used with single-point
spacecraft measurements to distinguish and characterize different
collisionless particle energization mechanisms.