SOLAR-WIND DENSITY INTERCOMPARISONS ON THE WIND SPACECRAFT USING WAVES AND SWE EXPERIMENTS

We present solar wind density comparisons using three different instru ments on the WIND spacecraft: The thermal noise receiver (TNR) on the WAVES experiment which yields the total electron density from the dete ction and the analysis of the electron plasma peak; the SWE Faraday cu p detectors which measure ion energy per charge spectra and yield the proton and alpha particle densities in the solar wind; and finally the SWE electron spectrometer which provides 3D electron velocity distrib ution functions and thus the total electron density. The density compa rison between the TNR and the SWE Faraday cups shows a remarkably good agreement, with a systematic offset which is lower than 1% and fluctu ations of up to approximate to 5% around this value. Due to the well k nown spacecraft electrical potential effects, the SWE electron spectro meter densities, uncorrected from the potential, exhibit larger differ ences when compared with the TNR or the SWE Faraday cups measurements. Using these latter densities as reference, we compute a rough estimat ion of the spacecraft potential.