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Effects of MHD shocks propagating along magnetic flux tubes in a dipole magnetic field
Erkaev N. V., Shaidurov V. A., Semenov V. S., Biernat H. K.
Nonlinear Processes in Geophysics. —
2002. — Vol. 9. — P. 163–172.
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Abstract
Variations of the plasma pressure in a magnetic
flux tube can produce MHD waves evolving into shocks. In the case of a low plasma beta, plasma pressure pulses in the
magnetic flux tube generate MHD slow shocks propagating
along the tube. For converging magnetic field lines, such
as in a dipole magnetic field, the cross section of the mag-netic
flux tube decreases enormously with increasing mag-netic
field strength. In such a case, the propagation of MHD
waves along magnetic flux tubes is rather different from that
in the case of uniform magnetic fields. In this paper, the propagation of MHD slow shocks is studied numerically us-ing
the ideal MHD equations in an approximation suitable
for a thin magnetic flux tube with a low plasma beta. The results obtained in the numerical study show that the jumps
in the plasma parameters at the MHD slow shock increase
greatly while the shock is propagating in the narrowing mag-netic
flux tube. The results are applied to the case of the
interaction between Jupiter and its satellite Io, the latter be-ing
considered as a source of plasma pressure pulses.
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