Paper presented at the 5th SOHO Workshop, 17-20 June, 1997, Oslo, Norway
CELIAS is a particle experiment which continuously observes the chemical, isotopic, and ionic composition of minor elements in the solar wind. The Proton Monitor of CELIAS provides information on basic plasma parameters such as velocity, kinetic temperature, density and out-of-ecliptic flow angle of protons. The high mass resolution of the MTOF-sensor makes the detection of hereto unobserved elements with a wide variety of first ionization potentials possible. Since the first ionization potential plays a crucial role in feeding the solar wind from solar surface material this feature is important for studying the conditions in the source region of the solar wind. The first determinations of neon isotopic abundances with CELIAS has yielded an excellent agreement with the earlier measurements with the Apollo-Foil Experiment, the 54Fe/56Fe ratio in the solar wind agrees with the terrestrial value. The charge state determination with CTOF is done with a time resolution of five minutes, hence allowing the study of small scale features in the solar wind flow which might become important for the interpretation for correlated observations with optical instruments. STOF continuously provides data on suprathermal ions and neutrals presumably generated in corrotating interaction regions.