Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Space-charge effect of the time-varying electron injection in a diode:
  classical and relativistic regimes   Conventionally, space-charge (SC) limited current density is defined as the
maximal cur- rent density allowed to traverse a diode under a DC voltage when a
time-invariant flow is injected from the cathode. In this work, we study the SC
limited current density under a time-varying injection for both classical and
relativistic regimes and determine the maxi- mal amount of limited current
density under certain conditions. Our simulations show that it is unlikely that
a time-varying injection emitted from cathode exceeds the known SC limits, in
either classical or relativistic regime.

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The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: cs
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: plasm-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg