PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
In the final part of Ulysses’ first orbit between heliographic latitudes +40° and ecliptic (at 0°) left edge of the
velocity track reveal typical for the activity minimum SW speeds within 700–800 km/s till latitude of ~33°.
From this point the recurrent velocity drops appear due to influence of the magnetic complex. These drops
became dipper as SC approached to the center of magnetic activity.
Thus the solar wind streams carry information on the solar magnetic fields through which they go away, in
form of velocity and plasma density variations resulted from the direct interactions of the plasma outflows
with solar magnetic fields.
Conclusion
The main conclusions of the study presented are the following:
• the solar wind streams with uniform velocity 700–800 km/s is exclusively a phenomenon of the
background Sun, that is Sun of low activity epoch when closed magnetic fields on it are either absent
or very weak;
• the solar magnetic fields are not only responsible for the corona formation and heating but also
control the stationary solar wind velocity, both through plasma flow - the magnetic field interaction;
• there is inverse coupling between the SW speeds and solar magnetic field strengths: the stronger the
closed magnetic fields the slower the solar wind and vice versa that points to SW plasma
deceleration in the magnetic field structures;
• SW plasma – solar magnetic fields interactions occur inside of the source surface where solar
magnetic fields of different types are located.
This work has been made under support of RFFI grant No.08-02-00070.
References
Gosling et al. (1995), The band of solar variability at low heliographic latitudes near solar activity minimum:
Plasma results from the Ulysses rapid latitude scan, Geophys. Res. Lett., 22, 3329–3332.
Grall, R.R., W.A. Coles, Klinglesmith M.T. et al. (1996), Rapid acceleration of the polar solar wind, Letters
to Nature, Nature, 379, 429–431.
Nikolskaya, K.I. (2007), Solar wind and magnetic fields of the Sun, in: Proc.XIth Pulk. Intern.Conf. On the
Solar Physics “Physical Nature of the Solar Activity and Prediction of its Geophysical Effects” (Pulkovo,
Russia, 2–7 July 2007), ed. By A. Stepanov, A. Solovyev, V. Zaitsev. Publ. GAO RAN, 277–280.
Offman, L., L.M. Davila, W.A. Coles et al. (1997), IPS observations of the solar wind velocity and the
acceleration mechanism, in: Proc. the31st ESLAB Symposium on Correlated Phenomena at the Sun,
heliosphere and in Geospace (Noordwijk, the Netherlans, 22–25 September 1997), ed. by E. Wilson, ESA
Publications Division ESTEC, Noordwijk, the Netherlands.
Woo, R., and S.R. Habbal (1997), Extension of coronal structure into interplanetary space, Geophys. Res.
Lett., 24, 1159–1162.
Woo, R., and S.R. Habbal (1999a), Radial evolution of density structure in the solar corona, Geophys. Res.
Lett., 26, 1793–1796.
Woo, R., and S.R. Habbal (1999b), Imprint of the Sun on the solar wind, Astrophys. J., 510, L69–L72.
Woo, R., and S.R. Habbal (2000), Connecting the Sun and the solar wind: Source regions of the fast wind
observed in interplanetary space, J. Geophys. Res., 105, 12667–12674.
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