PHYSICAL AND CHEMICAL CHARACTERISTICS OF THE ISM INSIDE AND OUTSIDE THE HELIOSPHERE

This paper summarizes some of the discussions of working group 8-9 dur ing the ISSI Conference on ''The Heliosphere in the Local Interstellar Medium''. Because the subject of these working groups has become sign ificantly broader during the last ten years, we have selected three to pics for which recent observations have modified and improved our know ledge of the heliosphere and the surrounding interstellar medium. Thes e topics are the number densities and ISM ionization states of hydroge n and helium, the newly discovered hot gas from the ''H wall'' seen in absorption, and the comparison between ISM and heliospheric minor ele ment abundances. Papers from this volume in which more details on thes e topics can be found are quoted throughout the report.