42,576 research outputs found
Spherically symmetric monopoles in noncommutative space
We construct a spherically symmetric noncommutative space in three dimensions
by foliating the space with concentric fuzzy spheres. We show how to construct
a gauge theory in this space and in particular we derive the noncommutative
version of a Yang-Mills-Higgs theory. We find numerical monopole solutions of
the equations of motion.Comment: 13 pages, 3 figure
The physics of twisted magnetic tubes rising in a stratified medium: two dimensional results
The physics of a twisted magnetic flux tube rising in a stratified medium is
studied using a numerical MHD code. The problem considered is fully
compressible (no Boussinesq approximation), includes ohmic resistivity, and is
two dimensional, i.e., there is no variation of the variables in the direction
of the tube axis. We study a high plasma beta case with small ratio of radius
to external pressure scaleheight. The results obtained can therefore be of
relevance to understand the transport of magnetic flux across the solar
convection zone.Comment: To be published in ApJ, Vol. 492, Jan 10th, 1998; 25 pages, 16
figures. NEW VERSION: THE PREVIOUS ONE DIDN'T PRINT CORRECTLY. The style file
overrulehere.sty is include
Generations of orthogonal surface coordinates
Two generation methods were developed for three dimensional flows where the computational domain normal to the surface is small. With this restriction the coordinate system requires orthogonality only at the body surface. The first method uses the orthogonal condition in finite-difference form to determine the surface coordinates with the metric coefficients and curvature of the coordinate lines calculated numerically. The second method obtains analytical expressions for the metric coefficients and for the curvature of the coordinate lines
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