Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-05T09:35:23.837Z Has data issue: false hasContentIssue false
  • English
  • Français

A two-dimensional analysis of the compressible flow near a reconnection site at the dayside magnetopause

Published online by Cambridge University Press:  01 February 2007

LARS G. WESTERBERG  and
HANS O. ÅKERSTEDT
LARS G. WESTERBERG
Affiliation:
Division of Fluid Mechanics, Luleå University of Technology, SE-971 87, Luleå, Sweden
HANS O. ÅKERSTEDT
Affiliation:
Division of Fluid Mechanics, Luleå University of Technology, SE-971 87, Luleå, Sweden
Get access Rights & Permissions [Opens in a new window]

Abstract.

A compressible model of the magnetosheath plasma flow is considered. Magnetic reconnection is assumed to occur in a region stretching from the sub-Solar point to the north. Two locations of the reconnection site are treated: two and four Earth radii from the sub-Solar point, respectively. By treating the transition layer as very thin, we solve the governing equations approximately using the method of matched asymptotic expansions. The behavior of the magnetic field and the plasma velocity close to a reconnection site during the transition from the magnetosheath to the magnetosphere is investigated. We also obtain the development of the transition layer thickness north and south of the reconnection point. The magnetopause transition layer is represented by a large-amplitude Alfvén wave implying that the density is approximately the same across the magnetopause boundary. In order to match the solutions we consider a compressible ideal magnetohydrodynamic model describing density, velocity and magnetic field variations along the outer magnetopause boundary. We also compare the analytical results with solutions from a numerical simulation. The compressible effects on the structure of the magnetic field and the total velocity evolution are visible but not dramatic. It is shown that the transition layer north of the reconnection point is thinner than to the south. The effect is stronger for reconnection at higher latitudes.

Type
Papers
Information
Journal of Plasma Physics , Volume 73 , Issue 1 , February 2007 , pp. 89 - 115
Copyright
Copyright © Cambridge University Press 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Axford, W. I. 1964 Viscous interaction between the Solar wind and the Earth's magnetosphere. Planet. Space Sci. 12, 45–53.CrossRefGoogle Scholar
Belenkaya, E. S. 2002 Two magnetized plasmas at the subsolar low shear magnetopause. Intl. J. Geomagn. Aeron. 3 (2), 157–166.Google Scholar
Cabannes, H. 1956 Tables pour la détermination des onde de chock détachees. Recherche Aéronaut. 49, 11–15.Google Scholar
Cooling, B. M. A., Owen, C. J. and Schwartz, S. J. 2001 Role of the magnetosheath flow in determining the motion of open flux tubes. J. Geophys. Res. 106 (A9), 18 763–18 775.CrossRefGoogle Scholar
Cowley, S. W. H. and Owen, C. J. 1989 A simple illustrative model of open flux tube motion over the dayside magnetopause. Planet. Space Sci. 37, 1461.CrossRefGoogle Scholar
DeHoffmann, F. and Teller, E. 1950 Magnetohydrodynamic shocks. Phys. Rev. Lett. 80, 692.Google Scholar
Haerendel, G., Paschmann, N., Sckoke, N. and Rosenbauer, H. 1978 The front side boundary layer of the magnetosphere and the problem of reconnection. J. Geophys. Res. 83, 3195.CrossRefGoogle Scholar
Heyn, M. F., Biernat, H. K., Semenov, V. S. and Kubyshkin, I. V. 1985 Dayside magnetopause reconnection. J. Geophys. Res. 90, 1781–1785.CrossRefGoogle Scholar
Jardine, M. and Priest, E. R. 1989 Compressible models of fast steady-state magnetic reconnection. J. Plasma Phys. 4 (1), 111–132.CrossRefGoogle Scholar
Merrill, R. T., McElhinny, M. W. and McFadden, P. L. 1996 The Magnetic Field of the Earth (Int. Geophys. Series, 63). San Diego, CA: Academic Press, p. 58.Google Scholar
Petscheck, H. E. 1964 Magnetic field annihilation. In: AAS—NASA Symp. on the Physics of Solar Flares, NASA Spec. Publ., SP-50, 425, 425–439.Google Scholar
Sato, T., Hayashi, T., Watanabe, K., Horiuchi, R., Tanaka, M., Sawairi, N. and Kusano, K. 1992 Role of compressibility on driven magnetic reconnection. Phys. Fluids 4 (2), 450–457.CrossRefGoogle Scholar
Semenov, V. S., Heyn, M. F. and Ivanov, I. B. 2004 Magnetic reconnection with space and time varying reconnection rates in a compressible plasma. Phys. Plasmas 11 (1), 62–70.CrossRefGoogle Scholar
Sonnerup, B. U. Ö. 1970 Magnetic-field re-connexion in a highly conducting incompressible fluid. J. Plasma Phys. 4, 161–174.CrossRefGoogle Scholar
Spreiter, J. R. and Stahara, S. 1980 A new predictive model for determining Solar wind terrestrial planet instructions. J. Geophys. Res. 85, 6769.CrossRefGoogle Scholar
Spreiter, J. R., Summers, A. L. and Alksne, A. Y. 1966 Hydromagnetic flow around the magnetosphere. Planet. Space Sci. 14, 223–253.CrossRefGoogle Scholar
Westerberg, L. G. and Åkerstedt, H. O. 2005a A two dimensional analysis of the flow past an open terrestrial magnetopause. J. Plasma Phys. 71 (5), 537–562.CrossRefGoogle Scholar
Westerberg, L. G. and Åkerstedt, H. O. 2005b A three dimensional analysis of the flow past an open terrestrial magnetopause. J. Plasma Phys. (doi: 10.1017/S0022377805004149).CrossRefGoogle Scholar