Hot Plasma Composition Analyzer (HPCA) Time of Flight, TOF, Counts, Level 2, Survey 10 s Data. The MMS HPCA instruments measure the energy and composition of magnetospheric plasmas in the energy range from 1 eV to 40 keV. An electrostatic energy analyzer (ESA) that is optically coupled to a carbon-foil based Time-of-Flight (TOF) section comprises each HPCA. The basic HPCA data product is an array of counts for 5 ion species, at 63 energies, for each of 16 elevation anodes. Sixteen basic products, also called azimuths, are acquired every 10 s; half a spacecraft spin period nominally has 16 azimuths. The five ion species are protons (H+), alpha particles (He++), helium ions (He+), singly charged Oxygen (O+), and background counts.