Magnetic Reconnectlon, Coalescence, and Turbulence in Current Sheets

  1. C. T. Russell,
  2. E. R. Priest and
  3. L. C. Lee
  1. Manfred Scholer

Published Online: 21 MAR 2013

DOI: 10.1029/GM058p0085

Physics of Magnetic Flux Ropes

Physics of Magnetic Flux Ropes

How to Cite

Scholer, M. (1990) Magnetic Reconnectlon, Coalescence, and Turbulence in Current Sheets, in Physics of Magnetic Flux Ropes (eds C. T. Russell, E. R. Priest and L. C. Lee), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM058p0085

Author Information

  1. Instiut für Extraterrestrische Physik Max-Planck-Instiut für Physik und Astrophysik, 8046 Garching, FRG

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1990

ISBN Information

Print ISBN: 9780875900261

Online ISBN: 9781118663868

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Keywords:

  • Solar photosphere;
  • Magnetic flux;
  • Astrophysics

Summary

Reconnection in a double periodic current sheet configuration is investigated by means of a two-dimensional compressible MHD code as an initial value problem. The numerical system has a length x of 4π and a height y of 2π, so that the minimum wave number in a Fourier series in x is 1/2 unit. Reconnection is initiated by adding fluctuations in the initial data. The numerical experiments are decay runs; no additional energy is added after time t = 0. When the noise is initially only in modes with an integer ky and kx with a flat energy spectrum, two islands grow in each current sheet within about 10 Alfvén transit times. When the noise is also distributed into the modes with ∣kx ∣ = 1/2, a single large sized island grows in each current sheet. In this case kinetic energy and enstrophy (mean square vorticity) production is considerably larger. In a third run, the energy in each of the modes with ∣kx ∣ = 1/2 has been reduced to 0.25% of the energy in each of the other modes. Two islands grow initially in each current sheet and start to coalesce after about 30 Alfvén transit times into one big island. Maximum kinetic energy and enstrophy production occurs during the final coalescence process. In terms of a Fourier decomposition, the final build-up of one large scale structure can be described as a backtransfer of magnetic excitation of low wavenumbers. It is suggested, that in three-dimensional current sheets the presence of turbulence will drive the growth of small-scale flux ropes, which ultimately merge to a size determined by the largest scale available to the system. The kinetic energy production seems to be independent of the magnetic Reynolds number.