Physics
Scientific paper
Jun 1993
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993adspr..13...57o&link_type=abstract
Advances in Space Research (ISSN 0273-1177), vol. 13, no. 6, p. 57-62.
Physics
48
Magnetic Clouds, Nonlinear Evolution Equations, Solar Magnetic Field, Solar Wind, Lorentz Force, Magnetic Flux, Pressure Gradients
Scientific paper
The dynamics of radially expanding magnetic clouds is rigorously analyzed within the framework of ideal MHD. The cloud is modelled as a cylindrically symmetric magnetic flux rope. In the force balance we include the gas pressure gradient and the Lorentz force. Interaction with the ambient solar wind due to expansion of the magnetic cloud is represented by a drag force proportional to the bulk velocity. We consider the self-similar expansion of a polytrope, and reduce the problem to an ordinary nonlinear differential equation for the evolution function. Analyzing the asymptotic behavior of the evolution function, we formulate theoretical expectations for the long-term behavior of cloud parameters. We focus on the temporal evolution of (1) the magnetic field strength; (2) the twist of the field lines; (3) the asymmetry of the total field profile; and (4) the bulk flow speed. We present data from two magnetic clouds observed at 1 AU and 2 AU, respectively, and find good agreement with theoretical expectations. For a peak magnetic field strength at 1 AU of 25 nT and a polytropic index of 0.5, we find that a magnetic cloud can be distinguished from the background interplanetary field up to a distance of about 5 AU. Taking larger magnetic fields and bigger polytropic indices this distance can double.
Burlaga Leonard Francis
Farrugia Charles J.
Osherovich Vladimir A.
No associations
LandOfFree
Dynamics of aging magnetic clouds does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dynamics of aging magnetic clouds, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dynamics of aging magnetic clouds will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1734134