Space plasma particle correlation: theory, simulation and measurement

Historically particle correlator instruments have provided insight into the missing link of experimental space plasma physics. Space plasma instrumentation is otherwise split into the dichotomy imposed by particle-wave duality, but the correlator bridges this di- vision by detecting and measuring the interaction between wave and particle. In the past the theory of particle correlation in space plasmas has mainly dealt with reso- nant particles bunched within potential waves. To detect this, the technique employed was to Fourier transform the autocorrelation of the detected particles: a line spectrum would then be interpreted as a particle-wave resonance. In this poster we develope a theory in which derives analytical expressions for particle autocorrelation functions and we argue that the particle correlation is involved in more than just resonant parti- cles. Indeed it can be employed to study the microphysics of space plasmas. We also discuss various techniques for analysing particle correlator data which complements and in certain cases surpasses the Fourier technique. The theory and techniques are illustrated and applied to data from the DWP correlator on the Cluster space mission. We also show Monte-Carlo simulations of the microscale physics involved in counting electrons in a space plasma.