The TWINS exospheric neutral H-density distribution under solar minimum conditions
Terrestrial exospheric atomic hydrogen (H) resonantly scatters solar Lyman-α (121.567 nm) radiation, observed as the glow of the H-geocorona. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) satellites are equiped with two Lyman-α line-of-sight Detectors (LADs) each. Since during th...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2011-12-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/29/2211/2011/angeo-29-2211-2011.pdf |
| _version_ | 1818520276172800000 |
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| author | J. H. Zoennchen J. J. Bailey U. Nass M. Gruntman H. J. Fahr J. Goldstein J. Goldstein |
| author_facet | J. H. Zoennchen J. J. Bailey U. Nass M. Gruntman H. J. Fahr J. Goldstein J. Goldstein |
| author_sort | J. H. Zoennchen |
| collection | DOAJ |
| description | Terrestrial exospheric atomic hydrogen (H) resonantly
scatters solar Lyman-α (121.567 nm) radiation, observed as the glow of the
H-geocorona. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS)
satellites are equiped with two Lyman-α line-of-sight Detectors (LADs) each.
Since during the past solar minimum conditions the relevant solar control
parameters practically did not vary, we are using LAD data between June and
September 2008 to create a time averaged hydrogen geocorona model
representative for these solar minimum conditions. In this averaged model we
assume that the H-geocorona is longitudinally symmetric with respect to the
earth-sun line. We find a 3-dimensional H-density distribution in the range
from 3 to 8 earth radii which with some caution can also be extrapolated to
larger distances. For lower geocentric distances than 3 earth radii a best
fitting r-dependent Chamberlain (1963)-like model is adapted. Main findings
are larger than conventionally expected H-densities at heights above 5 <I>R</I><sub>E</sub> and a pronounced day-to-night side H-density asymmetry. The
H-geocorona presented here should serve as a reference H-atmosphere for the
earth during solar minimum conditions. |
| first_indexed | 2024-12-11T01:35:11Z |
| format | Article |
| id | doaj.art-57f3bb82bbab4732b4f2c22e938c96c2 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-11T01:35:11Z |
| publishDate | 2011-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-57f3bb82bbab4732b4f2c22e938c96c22022-12-22T01:25:14ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762011-12-01292211221710.5194/angeo-29-2211-2011The TWINS exospheric neutral H-density distribution under solar minimum conditionsJ. H. Zoennchen0J. J. Bailey1U. Nass2M. Gruntman3H. J. Fahr4J. Goldstein5J. Goldstein6Argelander Institut für Astronomie, Astrophysics Department, University of Bonn, Auf dem Huegel 71, 53121 Bonn, GermanyUniversity of Southern California, Department of Astronautical Engineering, Viterbi School of Engineering, Los Angeles, CA 90089-1192, USAArgelander Institut für Astronomie, Astrophysics Department, University of Bonn, Auf dem Huegel 71, 53121 Bonn, GermanyUniversity of Southern California, Department of Astronautical Engineering, Viterbi School of Engineering, Los Angeles, CA 90089-1192, USAArgelander Institut für Astronomie, Astrophysics Department, University of Bonn, Auf dem Huegel 71, 53121 Bonn, GermanySouthwest Research Institute, San Antonio, TX, USAUniversity of Texas, San Antonio, San Antonio, TX, USATerrestrial exospheric atomic hydrogen (H) resonantly scatters solar Lyman-α (121.567 nm) radiation, observed as the glow of the H-geocorona. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) satellites are equiped with two Lyman-α line-of-sight Detectors (LADs) each. Since during the past solar minimum conditions the relevant solar control parameters practically did not vary, we are using LAD data between June and September 2008 to create a time averaged hydrogen geocorona model representative for these solar minimum conditions. In this averaged model we assume that the H-geocorona is longitudinally symmetric with respect to the earth-sun line. We find a 3-dimensional H-density distribution in the range from 3 to 8 earth radii which with some caution can also be extrapolated to larger distances. For lower geocentric distances than 3 earth radii a best fitting r-dependent Chamberlain (1963)-like model is adapted. Main findings are larger than conventionally expected H-densities at heights above 5 <I>R</I><sub>E</sub> and a pronounced day-to-night side H-density asymmetry. The H-geocorona presented here should serve as a reference H-atmosphere for the earth during solar minimum conditions.https://www.ann-geophys.net/29/2211/2011/angeo-29-2211-2011.pdf |
| spellingShingle | J. H. Zoennchen J. J. Bailey U. Nass M. Gruntman H. J. Fahr J. Goldstein J. Goldstein The TWINS exospheric neutral H-density distribution under solar minimum conditions Annales Geophysicae |
| title | The TWINS exospheric neutral H-density distribution under solar minimum conditions |
| title_full | The TWINS exospheric neutral H-density distribution under solar minimum conditions |
| title_fullStr | The TWINS exospheric neutral H-density distribution under solar minimum conditions |
| title_full_unstemmed | The TWINS exospheric neutral H-density distribution under solar minimum conditions |
| title_short | The TWINS exospheric neutral H-density distribution under solar minimum conditions |
| title_sort | twins exospheric neutral h density distribution under solar minimum conditions |
| url | https://www.ann-geophys.net/29/2211/2011/angeo-29-2211-2011.pdf |
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