Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Relativistic Expansion of Magnetic Loops at the Self-similar Stage II:
  Magnetized outflows interacting with the ambient plasma   We obtained self-similar solutions of relativistically expanding magnetic
loops by assuming axisymmetry and a purely radial flow. The stellar rotation
and the magnetic fields in the ambient plasma are neglected. We include the
Newtonian gravity of the central star. These solutions are extended from those
in our previous work (Takahashi, Asano, & Matsumoto 2009) by taking into
account discontinuities such as the contact discontinuity and the shock. The
global plasma flow consists of three regions, the outflowing region, the post
shocked region, and the ambient plasma. They are divided by two
discontinuities. The solutions are characterized by the radial velocity, which
plays a role of the self-similar parameter in our solutions. The shock Lorentz
factor gradually increases with radius. It can be approximately represented by
the power of radius with the power law index of 0.25.
  We also carried out magnetohydrodynamic simulations of the evolution of
magnetic loops to study the stability and the generality of our analytical
solutions. We used the analytical solutions as the initial condition and the
inner boundary conditions. We confirmed that our solutions are stable over the
simulation time and that numerical results nicely recover the analytical
solutions. We then carried out numerical simulations to study the generality of
our solutions by changing the power law index \delta of the ambient plasma
density \rho_0 \propto r^{-\delta}. We alter the power law index \delta from
3.5 in the analytical solutions. The analytical solutions are used as the
initial conditions inside the shock in all simulations. We observed that the
shock Lorentz factor increases with time when \delta is larger than 3, while it
decreases with time when \delta is smaller than 3. The shock Lorentz factor is
proportional to t^{(\delta-3)/2}. These results are consistent with the
analytical studies by Shapiro (1979).

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The categories of this paper are: mtrl-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: bayes-an
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The categories of this paper are: q-fin
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: funct-an
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ph