original_query: What is the purpose of measuring the magnetic field and velocity distribution functions of solar wind particles?
query: What is the purpose of measuring the magnetic field and velocity distribution functions of solar wind particles by the PlasMag instrument on DSCOVR?
answer: Measuring the magnetic field and velocity distribution functions of solar wind particles allows for early warning detection of solar activity that could damage satellites and ground infrastructure.  This is because the PlasMag instrument can provide a 15-60 minute warning before a coronal mass ejection (CME) reaches Earth.