Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observations and modelling of Helium lines in solar flares   We explore the response of the He II 304 {\AA} and He I 584 {\AA} line
intensities to electron beam heating in solar flares using radiative
hydrodynamic simulations. Comparing different electron beams parameters, we
found that the intensities of both He lines are very sensitive to the energy
flux deposited in the chromosphere, or more specifically to the heating rate,
with He II 304 {\AA} being more sensitive to the heating than He I 584 {\AA}.
Therefore, the He line ratio increases for larger heating rates in the
chromosphere. A similar trend is found in observations, using SDO/EVE He
irradiance ratios and estimates of the electron beam energy rate obtained from
hard X-ray data. From the simulations, we also found that spectral index of the
electrons can affect the He ratio but a similar effect was not found in the
observations.

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The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
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The categories of this paper are: chem-ph