ASPI EXPERIMENT - MEASUREMENTS OF FIELDS AND WAVES ON BOARD THE INTERBALL-1 SPACECRAFT

The plasma-wave experiment ASPI (analysis of spectra of plasma waves a nd instabilities) on board the INTERBALL spacecraft is a combined wave diagnostics experiment. It performs measurements of the DC and AC mag netic field vector by flux-gate and search-coil sensors, the DC and AC electric field vector by Langmuir double probes and the plasma curren t by Langmuir split probe. Preliminary data analysis shows the low noi se levels of the sensors and the compatibility of new data with the re sults of previous missions. During several months of in-orbit operatio n a rich collection of data was acquired, examples of which at the mag netopause and plasma shea are presented in second part of the paper.