Speaker
Description
We investigate the shape and extend of the solar wind transition surfaces, namely the slow (sonic), the fast magnetosonic and the Alven surface, as a function of heliospheric latitude using actual experimental data from Ulysses, Parker Solar Probe and Solar Orbiter pole to pole journey. We also derive the temporal variation of the radius of these surfaces using measurements from spacecraft at 1 au. Moreover, a semi-analytical calculation of the shape and extend of the heliosphere, the heliospheric termination shock and CR modulation is made based on spacecraft data input for the initial conditions. We estimate directly the consequences of the solar wind latitudinal variation on the shape of the termination shock. The model that we use is an approximate gas-dynamic model based on Fahr et al. 1993; Nerney & Suess 1995. We develop a semi-analytical model that can use any spacecraft measurements as data input to give the distance and shape of the termination shock from the Sun in a simple computational way that gives realistic results. A comparison is made of the Voyager crossing of the termination shock and NM CR data.
| Session | 1 - Cosmic Rays in the Heliosphere |
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