INTERACTION OF THE SOLAR-WIND WITH THE LOCAL INTERSTELLAR-MEDIUM - A MULTIFLUID APPROACH

A distinct fluid description for neutral. hydrogen originating from ei ther the interstellar medium, the heliosheath, or the solar wind has b een developed to describe the detailed interaction of the solar wind w ith the local interstellar medium (LISM) [Williams et al., 1995]. Such a multifluid description for the hydrogen serves to capture the highl y anisotropic nature of the neutral distribution. The neutral multiflu id is coupled to a hydrodynamic plasma through charge exchange and the time-dependent model is solved in two spatial dimensions. This approa ch is used (1) to elucidate the nature of the solar wind - LISM intera ction more carefully and precisely than has been done previously; (2) to identify precisely the role played by the three identifiably distin ct neutral populations in determining the global structure and dynamic s of the heliosphere (it is found, for example, that the heliopause is weakly time-dependent for the two-shock model); (3) to contract these results with those obtained from the simpler, computationally more ef ficient model developed by Pauls et al. [1995]; and (4) to investigate the differences in global heliospheric structure and neutral properti es between a two-shock (which results from a supersonic interstellar w ind impinging on the heliosphere) and a one-shock (i.e., for a subsoni c interstellar wind) model. In particular, observational criteria are presented that may allow one to distinguish between a one-shock and a two-shock heliosphere.