Estimation of wave vector characteristics

In the realistic case of multiple electromagnetic plasma wave sources and multiple propagation paths, auto-correlation and cross-correlation products of the six wave components can be utilized to fit model parameters for the wave normal vector and Poynting vector distribution functions. With the complete wave vector characteristics, the wave mode can be identified, the index of refraction derived and the wave ray traced back towards the wave source region. Plasma wave instrumentation suitable for estimating some wave vector characteristics has been carried on satellites starting with FR-1 in 1964 and has evolved in various configurations on OGO-5, Injun-5, GEOS, Voyager, ISEE, Dynamics Explorer and the proposed OPEN spacecraft. Plasma wave research needs to advance along two parallel lines: (a) developing more sophisticated computer techniques for extracting the wave vector information from extensive data sets and (b) utilizing microprocessor technology in flight instruments to recognize specified phenomena and to capture the appropriate wave data for further on-board or ground processing.