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A criterion for splitting of a reconnecting current sheet into MHD discontinuities

Published online by Cambridge University Press:  13 March 2009

S. A. Markovskii
Affiliation:
Solar Physics Department, Sternberg Astronomical Institute, Moscow State University, Moscow 119899, Russia
B. V. Somov
Affiliation:
Solar Physics Department, Sternberg Astronomical Institute, Moscow State University, Moscow 119899, Russia

Abstract

We consider the splitting of a reconnecting current sheet into MHD discontinuities, which is observed in many numerical simulations of the magnetic reconnection process. We suppose that the splitting takes place as a consequence of non-evolutionarity of the reconnecting current sheet as a onedimensional discontinuity. This means that the problem of the time evolution of its small perturbations does not have a unique solution. Since a physical problem must always have a unique solution, a non-evolutionary discontinuity cannot exist in a real plasma, and splits into evolutionary discontinuities. Solving the linear MHD equations inside and outside the sheet, we show that for large enough plasma conductivity, certain small perturbations interact with the sheet as with a discontinuity. On the basis of the non-evolutionarity criterion, with respect to these perturbations, we obtain a condition on the flow velocity at the sheet surface, under which the splitting takes place.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

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References

Akhiezer, A. I., Liubarskii, G. IA. & Polovin, R. V. 1959 The stability of shock waves in magnetohydrodynamics. Soviet Phys. JETP 8, 507511.Google Scholar
Anderson, J. E. 1963 Magnetohydrodynamic Shock Waves. MIT Press, Cambridge, MA.CrossRefGoogle Scholar
Biskamp, D. 1982 Effect of secondary tearing instability on the coalescence of magnetic islands. Phys. Lett. 87 A, 357360.CrossRefGoogle Scholar
Biskamp, D. 1986 Magnetic reconnection via current sheets. Phys. Fluids 29, 15201531.Google Scholar
Brushlinskii, K. V., Zaborov, A. M. & Syrovatskii, S. I. 1980 Numerical analysis of the current sheet near a magnetic null line. Soviet J. Plasma Phys. 6, 165173.Google Scholar
D'yakov, S. P. 1954 On the stability of shock waves. Zh. Eksp. Teor. Fiz. 27, 288295 (in Russian).Google Scholar
Forbes, T. G. & Priest, E. R. 1987 A comparison of analytical and numerical models for steady driven magnetic reconnection. Rev. Geophys. 25, 15831607.Google Scholar
Furth, H. P., Killen, J. & Rosenbluth, M. N. 1963 Finite-resistivity instability of a sheet pinch. Phys. Fluids 6, 459484.CrossRefGoogle Scholar
Hones, E. W. (ed.) 1984 Magnetic Reconnection in Space and Laboratory Plasmas. American Geophysical Union, Washington, DC.CrossRefGoogle Scholar
Kadomtsev, B. B. 1987 Magnetic field line reconnection. Rep. Prog. Phys. 50, 115143.Google Scholar
Kontorovich, V. M. 1959 On the interaction between small disturbances and the discontinuities in magnetohydrodynamics and on the stability of shock waves. Soviet Phys. JETP 8, 851858.Google Scholar
Petschek, H. E. 1964 Magnetic field annihilation. NASA Spec. Publ. SP-50, pp. 425439.Google Scholar
Priest, E. R. 1982 Solar Magnetohydrodynamics. Reidel, Dordrecht.Google Scholar
Priest, E. R. & Forbes, T. G. 1992 Does fast magnetic reconnection exist? J. Geophys. Res. 97, 1675716772.Google Scholar
Roikhvarger, Z. B. & Syrovatskii, S. I. 1974 Evolutionarity of magnetohydrodynamic discontinuities with allowance for dissipative waves. Soviet Phys. JETP 39, 654656.Google Scholar
Somov, B. V. 1992 Physical Processes in Solar Flares. Kluwer, Dordrecht.CrossRefGoogle Scholar
Somov, B. V. 1994 Fundamentals of Cosmic Electrodynamics. Kluwer, Dordrecht.Google Scholar
Somov, B. V. & Syrovatskii, S. I. 1976 Neutral current sheets in plasmas. Proceedings of P. N. Lebedev Physical Institute, Vol. 74, pp. 1371. Consultants Bureau, New York.Google Scholar
Syrovatskii, S. I. 1956 Some properties of surfaces of discontinuity in magnetohydrodynamics. Proceedings of P. N. Lebedev Physical Institute, Vol. 8, pp. 1364. Nauka, Moscow (in Russian).Google Scholar
Syrovatskii, S. I. 1959 The stability of shock waves in magnetohydrodynamics. Soviet Phys. JETP 8, 10241027.Google Scholar
Syrovatskii, S. I. 1971 Formation of current sheet in a plasma with a frozen-in strong magnetic field. Soviet Phys. JETP 33, 933940.Google Scholar
Syrovatskii, S. I. 1976a Characteristics of current sheet and thermal trigger of solar flares. Soviet Astron. Lett. 2, 1316.Google Scholar
Syrovatskii, S. I. 1976b Neutral current sheets in laboratory and space plasma. Proceedings of P. N. Lebedev Physical Institute, Vol. 74, pp. 212. Consultants Bureau, New York.Google Scholar