## 4. Parameters of the problemTaking into account Eq. (4) we obtain for the cosine of the angle between the magnetic field vector and the radial direction Furthermore we shall assume that where and in view of ULYSSES observations may depend on the colatitude (see Forsyth et al., (1996). Then by use of Eq. (4) we shall have for the last factor on the right-hand side of Eq. (26) It is known from ULYSSES observations that both and are latitude-dependent values (see e.g. Forsyth et al., (1996)). But we shall assume here that the ratio essentially behaves as a constant. On the other hand we shall consider the magnitude of this value as a free parameter. By use of Eq. (4) and adopting an electron number density according to , where = const, we can obtain Furthermore for this paper we shall specify pick-up ions as pick-up protons. The ratio for protons can be written as All calculations presented here were carried out using the
following values for the basic parameters:
km/s, km/s,
cm It can be shown from the definition (27) that at Since we can admit here that . Thus the diffusion coefficient (see Eq. (26)) depends only on two free parameters, namely and . © European Southern Observatory (ESO) 1998 Online publication: June 18, 1998 |