A theoretical model of the acceleration region of the solar wind with major species (p, c~, e) and minor ions (e.g., 3He, C, O, Mg, Si) is presented. Observed ne-profiles and the equations of continuity and momentum are used to calculate profiles of T, n, and u for all species, as well as charge states of minor ions. The disagreement of the results of a pure p-e model with observations is discussed in some detail, and it is shown that a model consistent with observations both in the corona and at 1 AU requires a finite abundance of He § +. This model predicts a strong enhancement of He/H in the lower corona. The results for the frozen-in charge states in the p-~-e model are in agreement with measurements in the low speed solar wind, especially for the well determined pair 06+/07+. Finally, a model for a coronal hole is investigated and it is found that wave pressure is necessary to model successfully the observed solar wind speeds and abundances.Although various simplifying assumptions had to be introduced, care was taken to ensure that the model remains physically consistent, i.e., that the same physics is used for the major species as well as the minor ions.
The Solar Wind and Suprathermal Ion Composition Experiment (SMS) on WIND is designed to determine uniquely the elemental, isotopic, and ionic-charge composition of the solar wind, the temperatures and mean speeds of all major solar-wind ions, from H through Fe, at solar wind speeds ranging from 175 kms-1 (protons) to 1280 kms-1 (Fe+8), and the composition, charge states as well as the 3-dimensional distribution functions of suprathermal ions, including interstellar pickup He +, of energies up to 230 keV/e. The experiment consists of three instruments with a common Data Processing Unit. Each of the three instruments uses electrostatic analysis followed by a time-of-flight and, as required, an energy measurement. The observations made by SMS will make valuable contributions to the ISTP objectives by providing information regarding the composition and energy distribution of matter entering the magnetosphere. In addition SMS results will have an impact on many areas of solar and heliospheric physics, in particular providing important and unique information on: (i) conditions and processes in the region of the corona where the solar wind is accelerated; (ii) the location of the source regions of the solar wind in the corona; (iii) coronal heating processes; (iv) the extent and causes of variations in the composition of the solar atmosphere; (v) plasma processes in the solar wind; (vi) the acceleration of particles in the solar wind; and (vii) the physics of the pickup process of interstellar He as well as lunar particles in the solar wind, and the isotopic composition of interstellar helium.
Abstract. The proton monitor, a small subsensor in the Charge, Element, and Isotope Analysis System/Mass Time-of-Flight (CELIAS/MTOF) experiment on the SOHO spacecraft, was designed to assist in the interpretation of measurements from the high mass resolution main MTOF sensor. In this paper we demonstrate that the proton monitor data may be used to generate reasonably accurate values of the solar wind proton bulk speed, density, thermal speed, and north/south flow direction. Correlation coefficients based on comparison with the solar wind measurements from the SWE instrument on the Wind spacecraft range from 0.87 to 0.99. On the basis of the initial 12 months of observations, we find that the proton momentum flux is almost invariant with respect to the bulk speed, confirming a previously published result. We present observations of two interplanetary shock events, and of an unusual solar wind density depletion. This large density depletion, and the correspondingly large drop in the solar wind ram pressure, may have been the cause of a nearly simultaneous large increase in the flux of relativistic magnetospheric electrons observed at geosynchronous altitudes by the GOES 9 spacecraft. Extending our data set with a 10-year time span from the OMNIWeb data set, we find an average frequency of about one large density depletion per year. The origin of these events is unclear; of the 10 events identified, 3 appear to be corotating and at least 2 are probably CME related. The rapidly available, comprehensive data coverage from SOHO allows the production of near-real time solar wind parameters that are now accessible on the World Wide Web. IntroductionThe The proton monitor is a subsensor of the MTOF experiment. MTOF determines high-resolution mass spectra of heavy solar wind ions and uses a very wide bandwidth energyper-charge analyzer to maximize counting statistics (at the expense of charge state information) for rare elements and isotopes. Since SOHO is not a spinning spacecraft, the deflection system was designed to have a wide angular acceptance in two dimensions. The PM was designed to assist in the interpretation of MTOF data and for that reason uses a similar wide bandwidth (and wide angular acceptance) analyzer that 17,205
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