Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diamagnetic "bubble" equilibria in linear traps   The plasma equilibrium in a linear trap at $\beta\approx 1$ (or above the
mirror-instability threshold) under the topology-conservation constraint
evolves into a kind of diamagnetic "bubble". This can take two forms: either
the plasma body greatly expands in radius while containing the same magnetic
flux, or, if the plasma radius is limited, the plasma distribution across
flux-tubes changes, so that the same cross-section contains a greatly reduced
flux. If the magnetic field of the trap is quasi-uniform around its minimum,
the bubble can be made roughly cylindrical, with radius much larger than the
radius of the corresponding vacuum flux-tube, and with non-paraxial ends. Then
the effective mirror ratio of the diamagnetic trap becomes very large, but the
cross-field transport increases. The confinement time can be found from
solution of the system of equilibrium and transport equations and is shown to
be $\tau_E\approx\sqrt{\tau_\parallel\tau_\perp}$. If the cross-field
confinement is not too degraded by turbulence, this estimate in principle
allows construction of relatively compact fusion reactors with lengths in the
range of a few tens of meters. In many ways the described here diamagnetic
confinement and the corresponding reactor parameters are similar to those
claimed by the FRCs.

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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin