Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dependence on ion temperature of shallow-angle magnetic presheaths with
  adiabatic electrons   The magnetic presheath is a boundary layer occurring when magnetized plasma
is in contact with a wall and the angle $\alpha$ between the wall and the
magnetic field $\vec{B}$ is oblique. Here, we consider the fusion-relevant case
of a shallow-angle, $\alpha \ll 1$, electron-repelling sheath, with the
electron density given by a Boltzmann distribution, valid for $\alpha /
\sqrt{\tau+1} \gg \sqrt{m_{\text{e}}/m_{\text{i}}}$, where $m_{\text{e}}$ is
the electron mass, $m_{\text{i}}$ is the ion mass, $\tau =
T_{\text{i}}/ZT_{\text{e}}$, $T_{\text{e}}$ is the electron temperature,
$T_{\text{i}}$ is the ion temperature, and $Z$ is the ionic charge state. The
thickness of the magnetic presheath is of the order of a few ion sound Larmor
radii $\rho_{\text{s}} = \sqrt{m_{\text{i}} \left(ZT_{\text{e}} + T_{\text{i}}
\right) } / ZeB$, where $e$ is the proton charge and $B = |\vec{B}|$ is the
magnitude of the magnetic field. We study the dependence on $\tau $ of the
electrostatic potential and ion distribution function in the magnetic presheath
by using a set of prescribed ion distribution functions at the magnetic
presheath entrance, parameterized by $\tau$. The kinetic model is shown to be
asymptotically equivalent to Chodura's fluid model at small ion temperature,
$\tau \ll 1$, for $|\ln \alpha| > 3|\ln \tau | \gg 1$. In this limit, despite
the fact that fluid equations give a reasonable approximation to the potential,
ion gyro-orbits acquire a spatial extent that occupies a large portion of the
magnetic presheath. At large ion temperature, $\tau \gg 1$, relevant because
$T_{\text{i}}$ is measured to be a few times larger than $T_{\text{e}}$ near
divertor targets of fusion devices, ions reach the Debye sheath entrance (and
subsequently the wall) at a shallow angle whose size is given by
$\sqrt{\alpha}$ or $1/\sqrt{\tau}$, depending on which is largest.

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The categories of this paper are: acc-phys
2
The categories of this paper are: math
7
The categories of this paper are: hep-th
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The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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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: solv-int
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: astro-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th