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| Titel |
A consistent thermodynamics of the MHD wave-heated two-fluid solar wind |
| VerfasserIn |
I. V. Chashei, H. J. Fahr  , G. Lay |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 21, no. 7 ; Nr. 21, no. 7, S.1405-1418 |
| Datensatznummer |
250014651
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| Publikation (Nr.) |
 copernicus.org/angeo-21-1405-2003.pdf |
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| Zusammenfassung |
We start our
considerations from two more recent findings in heliospheric physics: One is
the fact that the primary solar wind protons do not cool off adiabatically with
distance, but appear to be heated. The other one is that secondary protons,
embedded in the solar wind as pick-up ions, behave quasi-isothermal at their
motion to the outer heliosphere. These two phenomena must be physically closely
connected with each other. To demonstrate this we solve a coupled set of
enthalpy flow conservation equations for the two-fluid solar wind system
consisting of primary and secondary protons. The coupling of these equations
comes by the heat sources that are relevant, namely the dissipation of MHD
turbulence power to the respective protons at the relevant dissipation scales.
Hereby we consider both the dissipation of convected turbulences and the
dissipation of turbulences locally driven by the injection of new pick-up ions
into an unstable mode of the ion distribution function. Conversion of free
kinetic energy of freshly injected secondary ions into turbulence power is
finally followed by partial reabsorption of this energy both by primary and
secondary ions. We show solutions of simultaneous integrations of the coupled
set of differential thermodynamic two-fluid equations and can draw interesting
conclusions from the solutions obtained. We can show that the secondary proton
temperature with increasing radial distance asymptotically attains a constant
value with a magnitude essentially determined by the actual solar wind
velocity. Furthermore, we study the primary proton temperature within this
two-fluid context and find a polytropic behaviour with radially and
latitudinally variable polytropic indices determined by the local heat sources
due to dissipated turbulent wave energy. Considering latitudinally variable
solar wind conditions, as published by McComas et al. (2000), we also predict
latitudinal variations of primary proton temperatures at large solar distances.
Key words. Interplanetary physics
(interstellar gas, plasma waves and turbulence; solar wind plasma) |
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