Fast Solar Wind Monitor (BMSW): Description and First Results

Monitoring of solar wind parameters is a key problem of the Space Weather program. The paper presents a description of a novel fast solar wind monitor (Bright Monitor of the Solar Wind, BMSW) and the first results of its measurements of plasma moments with a time resolution ranging from seconds to 31 ms. The method of the fast monitoring is based on simultaneous measurements of the total ion flux and ion integral energy spectrum by six nearly identical Faraday cups (FCs). Three of them are dedicated to determination of the ion flow direction, whereas other three equipped with control grids supplied by a retarding potential are used for a determination of the density, temperature, and speed of the plasma flow. The paper introduces not only the measuring methods, the FCs design, and modes of operation, but brings the examples of time series of measurements and their comparison with the observations of other spacecraft as well as the first results of an analysis of frequency spectra of solar wind fluctuations within the ion kinetic scale, examples of rapid measurements at the ramp of an interplanetary shock and investigations of fast variations of alpha particle content.