Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Resistive Magnetohydrodynamic Equilibria in a Torus   It was recently demonstrated that static, resistive, magnetohydrodynamic
equilibria, in the presence of spatially-uniform electrical conductivity, do
not exist in a torus under a standard set of assumed symmetries and boundary
conditions. The difficulty, which goes away in the ``periodic straight cylinder
approximation,'' is associated with the necessarily non-vanishing character of
the curl of the Lorentz force, j x B. Here, we ask if there exists a spatial
profile of electrical conductivity that permits the existence of zero-flow,
axisymmetric r esistive equilibria in a torus, and answer the question in the
affirmative. However, the physical properties of the conductivity profile are
unusual (the conductivity cannot be constant on a magnetic surface, for
example) and whether such equilibria are to be considered physically possible
remains an open question.

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The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
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The categories of this paper are: nlin
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
0
The categories of this paper are: hep-ph