文章基本信息

标题：Energy spectra of carbon and oxygen with HELIOS E6
其他标题：Radial gradients of anomalous cosmic ray oxygen within 1 AU
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作者：J. Marquardt ; B. Heber ; M. S. Potgieter 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2018
卷号：610
DOI：10.1051/0004-6361/201731490
语种：English
出版社：EDP Sciences
摘要：Context.Anomalous cosmic rays (ACRs) are well-suited to probe the transport conditions of cosmic rays in the inner heliosphere. We revisit the HELIOS data not only in view of the upcoming Solar Orbiter experiment but also to put constraints on particle transport models in order to provide new insight into the boundary conditions close to the Sun.Aims.We present here the energy spectra of galactic cosmic ray (GCR) carbon and oxygen, as well as of ACR oxygen during solar quiet time periods between 1975 to 1977, utilizing both HELIOS spacecraft at distances between ~0.3 and 1 AU. The radial gradient (Gr≈ 50%/AU) of 9–28.5 MeV ACR oxygen in the inner heliosphere is about three times larger than the one determined between 1 and 10 AU by utilizing the Pioneer 10 measurements.Methods.The chemical composition as well as the energy spectra have been derived by applying the dE∕dx−E-method. In order to derive these values, special characteristics of the instrument have been taken into account.Results.A good agreement of the GCR energy spectra of carbon and oxygen measured by the HELIOS E6 instrument between 0.3 and 1 AU and the Interplanetary Monitoring Platform (IMP) 8 at 1 AU was found. For ACR oxygen, we determined a radial gradient of about 50%/AU that is three times larger than the one between 7 and 14 AU, indicating a strong change in the inner heliosphere.
关键词：Key wordsenSun: heliospheresolar-terrestrial relationscosmic rays