V.B. Baranov and M.G. Lebedev 1) Institute for Problems in Mechanics of Russian Academy of Science, 2) Moscow State University The sorrow fate of the solar wind protons in the shock layer on the cometary ionosphere ISSI Workshop, Bern, Switzerland, 20 – 24 January , 2)2)

One-fluid model taking into account “mass-loading” effect Qualitative picture of the solar wind interaction with a comet atmosphere (without dust component) (Biermann, Brosowski, Schmidt, Solar Physics, 1967, pioneer paper) BS – bow shock in the solar wind wind CD – contact discontinuity separating the solar wind and a charged component of a comet ionosphere IS – inner shock wave in a comet ionosphere, a distance from a comet nuclear at which neutrals and ions will be collisionless

Single-fluid equations describing the solar wind interaction with comet atmospheres. = const - Radial velocity of the cometary molecules - Number of molecules outflowing from a cometary nucleus per second - Photoionization frequency of cometary molecules

The solar wind velocity as a function of time along the trajectory of the Suissei spacecraft during its encounter with the comet Halley Solid line – the theoretical curve (Baranov, Lebedev, Astrophys. Space Sci., 1988), Points – experimental data Bulk velocity (km/c) 8 March 1986

Comparison of the calculated (red curve) and measured (JPA and PICCA instruments) velocities along the GIOTTO path

Measured proton and water group ion temperatures along the GIOTTO path

Number density of cometary ions along the trajectory of Giotto-spacecraft near the comet Halley 1 – theoretical curve (Baranov, Lebedev, Astrophys. And Space Sci., 1988; Astron. and Astrophys., 1993) 2 – measurements by PICCA - instrument (Korth et al., Astron. Astrophys., 1987) 3 – measurements by JPA - instrument (Formisano et al., Astron. Astrophys., 1990) 4 – measurements by IMS -instrument (Neugebauer et al., Astron. Astrophys., 1992)

Additional equations for proton and ion distribution of densities inside of the shock layer (between BS and CD) Continuum equations for protons and water ions. From these equations we obtain distributions of the solar wind proton and “mass-loaded” ion densities knowing the solution of the one-fluid approximation (Baranov and Lebedev, 2013, not published)

Density of the solar wind protons and the “picked-up” water group ions as functions of the distance from the comet nucleus along the axis of symmetry (a) and the terminator (b)

The solar wind mass densities of nucleons (a) and protons (c) and Mach number (b) (a) (b) (c)

Total and proton densities in the solar wind along the theoretical (Baranov and Lebedev, 2013) bow shock (BS) and contact discontinuity (CD)

Comparison of the measured (Formisano et al.; Balsiger et al.) and calculated (B & L ; Benna) proton distributions along the GIOTTO path

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