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Fluid Aspects of Solar Wind Disturbances Driven by Coronal Mass EjectionsTransient disturbances in the solar wind initiated by coronal eruptions have been modeled for many years, beginning with the self-similar analytical models of Parker and Simon and Axford. The first numerical computer code (one-dimensional, gas dynamic) to study disturbance propagation in the solar wind was developed in the late 1960s, and a variety of other codes ranging from simple one-dimensional gas dynamic codes through three-dimensional gas dynamic and magnetohydrodynamic codes have been developed in subsequent years. For the most part, these codes have been applied to the problem of disturbances driven by fast CMEs propagating into a structureless solar wind. Pizzo provided an excellent summary of the level of understanding achieved from such simulation studies through about 1984, and other reviews have subsequently become available. More recently, some attention has been focused on disturbances generated by slow CMEs, on disturbances driven by CMEs having high internal pressures, and disturbance propagation effects associated with a structured ambient solar wind. Our purpose here is to provide a brief tutorial on fluid aspects of solar wind disturbances derived from numerical gas dynamic simulations. For the most part we illustrate disturbance evolution by propagating idealized perturbations, mimicking different types of CMEs, into a structureless solar wind using a simple one-dimensional, adiabatic (except at shocks), gas dynamic code. The simulations begin outside the critical point where the solar wind becomes supersonic and thus do not address questions of how the CMEs themselves are initiated. Limited to one dimension (the radial direction), the simulation code predicts too strong an interaction between newly ejected solar material and the ambient wind because it neglects azimuthal and meridional motions of the plasma that help relieve pressure stresses. Moreover, the code ignores magnetic forces and thus also underestimates the speed with which pressure disturbances propagate in the wind.
Document ID
20010038050
Acquisition Source
Headquarters
Document Type
Preprint (Draft being sent to journal)
Authors
Gosling, J. T. (Los Alamos National Lab. NM United States)
Riley, Pete (Science Applications International Corp. San Diego, CA United States)
Date Acquired
September 7, 2013
Publication Date
February 28, 2001
Publication Information
Publication: An Investigation of the Large Scale Evolution and Topology of Coronal Mass Ejections in the Solar Wind
Issue: Appedix 3
Subject Category
Solar Physics
Report/Patent Number
LA-UR-99-5887
Funding Number(s)
CONTRACT_GRANT: W-7405-eng-36
CONTRACT_GRANT: NASW-98007
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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