Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles
Long‐term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm ind...
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| Veröffentlicht in: | Journal of geophysical research. Space physics 2017-05, Vol.122 (5), p.5224-5234 |
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| creator | Li, X. Baker, D. N. Zhao, H. Zhang, K. Jaynes, A. N. Schiller, Q. Kanekal, S. G. Blake, J. B. Temerin, M. |
| description | Long‐term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm index (Dst), >2 MeV electrons at geostationary orbit, and ~2 MeV electrons across various L shells measured by Solar Anomalous Magnetospheric Particle Explorer in low Earth orbit (LEO) and by the Van Allen Probes/Relativistic Electron and Proton Telescope (REPT) in a geotransfer‐like orbit; the latter measurements are normalized to LEO based on comparison with Colorado Student Space Weather Experiment/Relativistic Electron and Proton Telescope integrated little experiment (REPTile) measurements in LEO. The average ratio of REPTile/REPT varies in a systematic manner with L, ~16% at L = 2.7, decreasing with L and reaching ~0.7% at L = 4.7, and increasing again with L though with greater uncertainty. We show that there have been no ~2 MeV electron enhancements inside L ~ 2.6 since 2006, prior to which numerous penetrations of ~2 MeV electrons into L |
| doi_str_mv | 10.1002/2017JA023924 |
| format | Article |
| fullrecord | <record><control><sourceid>proquest_cross</sourceid><recordid>TN_cdi_proquest_journals_1911122178</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>1911122178</sourcerecordid><originalsourceid>FETCH-LOGICAL-c3453-8b28d869830f197211fbf53b64a82e43c365ebc1f624d0ccd9fc709619d8ef733</originalsourceid><addsrcrecordid>eNp9kE9LAzEQxRdRsNTe_AABLwquZpL9k4iXpWi1FJSiXpdsdgJb0k1Nti377V2pgifn8t4MP-bBi6JzoDdAKbtlFPJ5QRmXLDmKRgwyGcuEsuNfzwU9jSYhrOgwYjhBOopwqepGdY1rSYW2I2hRd37Y6r5V60YHojpi3Z4syOV9cnVHPlRLCmuxJa_eVRgIekV26MM2kI3HXeMG0-0dCc4qT3SvLYaz6MQoG3Dyo-Po_fHhbfoUL15mz9NiEWuepDwWFRO1yKTg1IDMGYCpTMqrLFGCYcI1z1KsNJiMJTXVupZG51RmIGuBJud8HF0c_m68-9xi6MqV2_p2iCxBAgBjkIuBuj5Q2rsQPJpy45u18n0JtPzusvzb5YDzA75vLPb_suV8tixSnlLOvwBWtHNa</addsrcrecordid><sourcetype>Aggregation Database</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1911122178</pqid></control><display><type>article</type><title>Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles</title><source>Wiley Online Library Journals Frontfile Complete</source><source>Wiley Online Library Free Content</source><creator>Li, X. ; Baker, D. N. ; Zhao, H. ; Zhang, K. ; Jaynes, A. N. ; Schiller, Q. ; Kanekal, S. G. ; Blake, J. B. ; Temerin, M.</creator><creatorcontrib>Li, X. ; Baker, D. N. ; Zhao, H. ; Zhang, K. ; Jaynes, A. N. ; Schiller, Q. ; Kanekal, S. G. ; Blake, J. B. ; Temerin, M.</creatorcontrib><description>Long‐term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm index (Dst), >2 MeV electrons at geostationary orbit, and ~2 MeV electrons across various L shells measured by Solar Anomalous Magnetospheric Particle Explorer in low Earth orbit (LEO) and by the Van Allen Probes/Relativistic Electron and Proton Telescope (REPT) in a geotransfer‐like orbit; the latter measurements are normalized to LEO based on comparison with Colorado Student Space Weather Experiment/Relativistic Electron and Proton Telescope integrated little experiment (REPTile) measurements in LEO. The average ratio of REPTile/REPT varies in a systematic manner with L, ~16% at L = 2.7, decreasing with L and reaching ~0.7% at L = 4.7, and increasing again with L though with greater uncertainty. We show that there have been no ~2 MeV electron enhancements inside L ~ 2.6 since 2006, prior to which numerous penetrations of ~2 MeV electrons into L < 2.5 were measured during periods of stronger solar wind conditions (in terms of high‐speed solar wind, magnitude of interplanetary magnetic field, B, and a sustained southward Bz) and thus stronger geomagnetic activity. We conclude that results from the Van Allen Probes, which have been providing the finest measurements but in operation during a quiet solar activity period, may not be representative of radiation belt dynamics, particularly for the inner edge of the outer belt, during other solar cycle phases.
Key Points
Demonstrated for the first time the ratio of low Earth orbit measurements of ~2 MeV electrons versus measurements in a geotransfer‐like orbit
No ~2 MeV electrons inside of L ~ 2.6 since 2005, while numerous penetrations of ~2 MeV electrons inside L of 2.6 occurred before
Three solar wind criteria are presented to determine whether ~2 MeV electron enhancements will occur inside L of 2.6</description><identifier>ISSN: 2169-9380</identifier><identifier>EISSN: 2169-9402</identifier><identifier>DOI: 10.1002/2017JA023924</identifier><language>eng</language><publisher>Washington: Blackwell Publishing Ltd</publisher><subject>Charged particles ; Climatology ; Criteria ; CSSWE mission ; Dynamics ; Earth magnetosphere ; Earth orbits ; Electron density ; Electron flux ; Geomagnetic activity ; Geomagnetism ; High speed ; Interplanetary magnetic field ; Low earth orbits ; Magnetic fields ; Magnetospheres ; outer radiation belt ; Phases ; Probes ; Radiation ; Relativism ; Reptiles ; SAMPEX mission ; slot and inner belt ; Solar activity ; Solar cycle ; Solar wind ; solar wind conditions ; Solar wind velocity ; Space weather ; Storm index ; Time measurement ; Van Allen Probes ; Wind speed</subject><ispartof>Journal of geophysical research. Space physics, 2017-05, Vol.122 (5), p.5224-5234</ispartof><rights>2017. The Authors.</rights><rights>2017. American Geophysical Union. All Rights Reserved.</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c3453-8b28d869830f197211fbf53b64a82e43c365ebc1f624d0ccd9fc709619d8ef733</citedby><cites>FETCH-LOGICAL-c3453-8b28d869830f197211fbf53b64a82e43c365ebc1f624d0ccd9fc709619d8ef733</cites><orcidid>0000-0001-5909-0926 ; 0000-0001-8292-7691 ; 0000-0002-1683-3192 ; 0000-0002-1470-4266 ; 0000-0002-5169-5565 ; 0000-0001-7439-4362</orcidid></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><linktopdf>$$Uhttps://onlinelibrary.wiley.com/doi/pdf/10.1002%2F2017JA023924$$EPDF$$P50$$Gwiley$$Hfree_for_read</linktopdf><linktohtml>$$Uhttps://onlinelibrary.wiley.com/doi/full/10.1002%2F2017JA023924$$EHTML$$P50$$Gwiley$$Hfree_for_read</linktohtml><link.rule.ids>314,776,780,1411,1427,27901,27902,45550,45551,46384,46808</link.rule.ids></links><search><creatorcontrib>Li, X.</creatorcontrib><creatorcontrib>Baker, D. N.</creatorcontrib><creatorcontrib>Zhao, H.</creatorcontrib><creatorcontrib>Zhang, K.</creatorcontrib><creatorcontrib>Jaynes, A. N.</creatorcontrib><creatorcontrib>Schiller, Q.</creatorcontrib><creatorcontrib>Kanekal, S. G.</creatorcontrib><creatorcontrib>Blake, J. B.</creatorcontrib><creatorcontrib>Temerin, M.</creatorcontrib><title>Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles</title><title>Journal of geophysical research. Space physics</title><description>Long‐term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm index (Dst), >2 MeV electrons at geostationary orbit, and ~2 MeV electrons across various L shells measured by Solar Anomalous Magnetospheric Particle Explorer in low Earth orbit (LEO) and by the Van Allen Probes/Relativistic Electron and Proton Telescope (REPT) in a geotransfer‐like orbit; the latter measurements are normalized to LEO based on comparison with Colorado Student Space Weather Experiment/Relativistic Electron and Proton Telescope integrated little experiment (REPTile) measurements in LEO. The average ratio of REPTile/REPT varies in a systematic manner with L, ~16% at L = 2.7, decreasing with L and reaching ~0.7% at L = 4.7, and increasing again with L though with greater uncertainty. We show that there have been no ~2 MeV electron enhancements inside L ~ 2.6 since 2006, prior to which numerous penetrations of ~2 MeV electrons into L < 2.5 were measured during periods of stronger solar wind conditions (in terms of high‐speed solar wind, magnitude of interplanetary magnetic field, B, and a sustained southward Bz) and thus stronger geomagnetic activity. We conclude that results from the Van Allen Probes, which have been providing the finest measurements but in operation during a quiet solar activity period, may not be representative of radiation belt dynamics, particularly for the inner edge of the outer belt, during other solar cycle phases.
Key Points
Demonstrated for the first time the ratio of low Earth orbit measurements of ~2 MeV electrons versus measurements in a geotransfer‐like orbit
No ~2 MeV electrons inside of L ~ 2.6 since 2005, while numerous penetrations of ~2 MeV electrons inside L of 2.6 occurred before
Three solar wind criteria are presented to determine whether ~2 MeV electron enhancements will occur inside L of 2.6</description><subject>Charged particles</subject><subject>Climatology</subject><subject>Criteria</subject><subject>CSSWE mission</subject><subject>Dynamics</subject><subject>Earth magnetosphere</subject><subject>Earth orbits</subject><subject>Electron density</subject><subject>Electron flux</subject><subject>Geomagnetic activity</subject><subject>Geomagnetism</subject><subject>High speed</subject><subject>Interplanetary magnetic field</subject><subject>Low earth orbits</subject><subject>Magnetic fields</subject><subject>Magnetospheres</subject><subject>outer radiation belt</subject><subject>Phases</subject><subject>Probes</subject><subject>Radiation</subject><subject>Relativism</subject><subject>Reptiles</subject><subject>SAMPEX mission</subject><subject>slot and inner belt</subject><subject>Solar activity</subject><subject>Solar cycle</subject><subject>Solar wind</subject><subject>solar wind conditions</subject><subject>Solar wind velocity</subject><subject>Space weather</subject><subject>Storm index</subject><subject>Time measurement</subject><subject>Van Allen Probes</subject><subject>Wind speed</subject><issn>2169-9380</issn><issn>2169-9402</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2017</creationdate><recordtype>article</recordtype><sourceid>24P</sourceid><recordid>eNp9kE9LAzEQxRdRsNTe_AABLwquZpL9k4iXpWi1FJSiXpdsdgJb0k1Nti377V2pgifn8t4MP-bBi6JzoDdAKbtlFPJ5QRmXLDmKRgwyGcuEsuNfzwU9jSYhrOgwYjhBOopwqepGdY1rSYW2I2hRd37Y6r5V60YHojpi3Z4syOV9cnVHPlRLCmuxJa_eVRgIekV26MM2kI3HXeMG0-0dCc4qT3SvLYaz6MQoG3Dyo-Po_fHhbfoUL15mz9NiEWuepDwWFRO1yKTg1IDMGYCpTMqrLFGCYcI1z1KsNJiMJTXVupZG51RmIGuBJud8HF0c_m68-9xi6MqV2_p2iCxBAgBjkIuBuj5Q2rsQPJpy45u18n0JtPzusvzb5YDzA75vLPb_suV8tixSnlLOvwBWtHNa</recordid><startdate>201705</startdate><enddate>201705</enddate><creator>Li, X.</creator><creator>Baker, D. N.</creator><creator>Zhao, H.</creator><creator>Zhang, K.</creator><creator>Jaynes, A. N.</creator><creator>Schiller, Q.</creator><creator>Kanekal, S. G.</creator><creator>Blake, J. B.</creator><creator>Temerin, M.</creator><general>Blackwell Publishing Ltd</general><scope>24P</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>7TG</scope><scope>8FD</scope><scope>H8D</scope><scope>KL.</scope><scope>L7M</scope><orcidid>https://orcid.org/0000-0001-5909-0926</orcidid><orcidid>https://orcid.org/0000-0001-8292-7691</orcidid><orcidid>https://orcid.org/0000-0002-1683-3192</orcidid><orcidid>https://orcid.org/0000-0002-1470-4266</orcidid><orcidid>https://orcid.org/0000-0002-5169-5565</orcidid><orcidid>https://orcid.org/0000-0001-7439-4362</orcidid></search><sort><creationdate>201705</creationdate><title>Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles</title><author>Li, X. ; Baker, D. N. ; Zhao, H. ; Zhang, K. ; Jaynes, A. N. ; Schiller, Q. ; Kanekal, S. G. ; Blake, J. B. ; Temerin, M.</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c3453-8b28d869830f197211fbf53b64a82e43c365ebc1f624d0ccd9fc709619d8ef733</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2017</creationdate><topic>Charged particles</topic><topic>Climatology</topic><topic>Criteria</topic><topic>CSSWE mission</topic><topic>Dynamics</topic><topic>Earth magnetosphere</topic><topic>Earth orbits</topic><topic>Electron density</topic><topic>Electron flux</topic><topic>Geomagnetic activity</topic><topic>Geomagnetism</topic><topic>High speed</topic><topic>Interplanetary magnetic field</topic><topic>Low earth orbits</topic><topic>Magnetic fields</topic><topic>Magnetospheres</topic><topic>outer radiation belt</topic><topic>Phases</topic><topic>Probes</topic><topic>Radiation</topic><topic>Relativism</topic><topic>Reptiles</topic><topic>SAMPEX mission</topic><topic>slot and inner belt</topic><topic>Solar activity</topic><topic>Solar cycle</topic><topic>Solar wind</topic><topic>solar wind conditions</topic><topic>Solar wind velocity</topic><topic>Space weather</topic><topic>Storm index</topic><topic>Time measurement</topic><topic>Van Allen Probes</topic><topic>Wind speed</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Li, X.</creatorcontrib><creatorcontrib>Baker, D. N.</creatorcontrib><creatorcontrib>Zhao, H.</creatorcontrib><creatorcontrib>Zhang, K.</creatorcontrib><creatorcontrib>Jaynes, A. N.</creatorcontrib><creatorcontrib>Schiller, Q.</creatorcontrib><creatorcontrib>Kanekal, S. G.</creatorcontrib><creatorcontrib>Blake, J. B.</creatorcontrib><creatorcontrib>Temerin, M.</creatorcontrib><collection>Wiley Online Library Open Access</collection><collection>CrossRef</collection><collection>Meteorological & Geoastrophysical Abstracts</collection><collection>Technology Research Database</collection><collection>Aerospace Database</collection><collection>Meteorological & Geoastrophysical Abstracts - Academic</collection><collection>Advanced Technologies Database with Aerospace</collection><jtitle>Journal of geophysical research. Space physics</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Li, X.</au><au>Baker, D. N.</au><au>Zhao, H.</au><au>Zhang, K.</au><au>Jaynes, A. N.</au><au>Schiller, Q.</au><au>Kanekal, S. G.</au><au>Blake, J. B.</au><au>Temerin, M.</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles</atitle><jtitle>Journal of geophysical research. Space physics</jtitle><date>2017-05</date><risdate>2017</risdate><volume>122</volume><issue>5</issue><spage>5224</spage><epage>5234</epage><pages>5224-5234</pages><issn>2169-9380</issn><eissn>2169-9402</eissn><abstract>Long‐term (>2 solar cycles) measurements reveal that MeV electron fluxes, solar wind speed, and geomagnetic activity have been extremely low during this current solar cycle, including years before and during the Van Allen Probes era. This study examines solar wind speed, the geomagnetic storm index (Dst), >2 MeV electrons at geostationary orbit, and ~2 MeV electrons across various L shells measured by Solar Anomalous Magnetospheric Particle Explorer in low Earth orbit (LEO) and by the Van Allen Probes/Relativistic Electron and Proton Telescope (REPT) in a geotransfer‐like orbit; the latter measurements are normalized to LEO based on comparison with Colorado Student Space Weather Experiment/Relativistic Electron and Proton Telescope integrated little experiment (REPTile) measurements in LEO. The average ratio of REPTile/REPT varies in a systematic manner with L, ~16% at L = 2.7, decreasing with L and reaching ~0.7% at L = 4.7, and increasing again with L though with greater uncertainty. We show that there have been no ~2 MeV electron enhancements inside L ~ 2.6 since 2006, prior to which numerous penetrations of ~2 MeV electrons into L < 2.5 were measured during periods of stronger solar wind conditions (in terms of high‐speed solar wind, magnitude of interplanetary magnetic field, B, and a sustained southward Bz) and thus stronger geomagnetic activity. We conclude that results from the Van Allen Probes, which have been providing the finest measurements but in operation during a quiet solar activity period, may not be representative of radiation belt dynamics, particularly for the inner edge of the outer belt, during other solar cycle phases.
Key Points
Demonstrated for the first time the ratio of low Earth orbit measurements of ~2 MeV electrons versus measurements in a geotransfer‐like orbit
No ~2 MeV electrons inside of L ~ 2.6 since 2005, while numerous penetrations of ~2 MeV electrons inside L of 2.6 occurred before
Three solar wind criteria are presented to determine whether ~2 MeV electron enhancements will occur inside L of 2.6</abstract><cop>Washington</cop><pub>Blackwell Publishing Ltd</pub><doi>10.1002/2017JA023924</doi><tpages>11</tpages><orcidid>https://orcid.org/0000-0001-5909-0926</orcidid><orcidid>https://orcid.org/0000-0001-8292-7691</orcidid><orcidid>https://orcid.org/0000-0002-1683-3192</orcidid><orcidid>https://orcid.org/0000-0002-1470-4266</orcidid><orcidid>https://orcid.org/0000-0002-5169-5565</orcidid><orcidid>https://orcid.org/0000-0001-7439-4362</orcidid><oa>free_for_read</oa></addata></record> |
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| ispartof | Journal of geophysical research. Space physics, 2017-05, Vol.122 (5), p.5224-5234 |
| issn | 2169-9380 2169-9402 |
| language | eng |
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| source | Wiley Online Library Journals Frontfile Complete; Wiley Online Library Free Content |
| subjects | Charged particles Climatology Criteria CSSWE mission Dynamics Earth magnetosphere Earth orbits Electron density Electron flux Geomagnetic activity Geomagnetism High speed Interplanetary magnetic field Low earth orbits Magnetic fields Magnetospheres outer radiation belt Phases Probes Radiation Relativism Reptiles SAMPEX mission slot and inner belt Solar activity Solar cycle Solar wind solar wind conditions Solar wind velocity Space weather Storm index Time measurement Van Allen Probes Wind speed |
| title | Radiation belt electron dynamics at low L (<4): Van Allen Probes era versus previous two solar cycles |
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