Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Heliospheric Magnetic Field 1835-2009   We use recently acquired geomagnetic archival data to extend our long-term
reconstruction of the HMF strength. The 1835-2009 HMF series is based on an
updated and substantiated IDV series from 1872-onwards and on Bartels'
extension, by proxy, of his u-series from 1835-1871. The new IDV series, termed
IDV09, has excellent agreement (R^2 = 0.98; RMS = 0.3 nT) with the earlier
IDV05 series, and also with the negative component of Love's extended (to 1905)
Dst series (R^2 = 0.91). Of greatest importance to the community, in an area of
research that has been contentious, comparison of the extended HMF series with
other recent reconstructions of solar wind B for the last ~100 years yields a
strong consensus between series based on geomagnetic data. Differences exist
from ~1900-1910 but they are far smaller than the previous disagreement for
this key interval of low solar wind B values which closely resembles current
solar activity. Equally encouraging, a discrepancy with an HMF reconstruction
based on 10Be data for the first half of the 20th century has largely been
removed by a revised 10Be-based reconstruction published after we submitted
this paper, although a remaining discrepancy for the years ~1885-1905 will need
to be resolved.

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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-th
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The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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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: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an