Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region
The “zebra stripes” are drift-periodic structures present in the form of peaks and valleys in energetic (tens to hundreds of keV) electron spectrograms in the Earth’s inner belt and slot region. Their characteristics inform of preceding electric field disturbances. Specifically, their amplitude cont...
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| Format: | Article |
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Frontiers Media S.A.
2022-02-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fspas.2022.823695/full |
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| author | Solène Lejosne Bela G. Fejer Naomi Maruyama Ludger Scherliess |
| author_facet | Solène Lejosne Bela G. Fejer Naomi Maruyama Ludger Scherliess |
| author_sort | Solène Lejosne |
| collection | DOAJ |
| description | The “zebra stripes” are drift-periodic structures present in the form of peaks and valleys in energetic (tens to hundreds of keV) electron spectrograms in the Earth’s inner belt and slot region. Their characteristics inform of preceding electric field disturbances. Specifically, their amplitude contains information on the radial transport of trapped particles generated by azimuthal electric field disturbances. We introduce a method to quantify radial transport from the measured amplitude of the zebra stripes, and we apply it to the zebra stripes observed on 16 February 2014. The findings are compared with results from a particle tracing code that leverages an empirical analytical model for the electric field disturbances. The measured amplitude of the zebra stripes indicates that the electric field disturbances transported the trapped population coherently, over radial distances spanning several hundreds to thousands of kilometers. The magnitude of radial transport is shown to depend on angular drift frequency and initial location (equatorial radial distance and magnetic local time) in the disturbance. The model-observation comparison suggests that the timing for electric field variations provided by the model is valid for studying radial transport in the inner belt and slot region. On the other hand, we found discrepancies when comparing radial transport magnitudes. When assuming that radial transport varies as L3, as weakly suggested by the data for set angular drift frequencies, and extrapolating observations to L = 1, the amount of experimental transport obtained is two to three times greater than numerical estimates. Outputs from the standalone version of the Rice Convection Model (RCM) suggests that the electric field disturbances are likely greater than the estimates provided by the empirical model. RCM also supports the idea that radial transport driven by the prompt penetration of magnetospheric convection varies as L3 in the inner belt and slot region. |
| first_indexed | 2024-12-13T03:28:48Z |
| format | Article |
| id | doaj.art-73bec63267874935a03e54154dfa4a38 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-12-13T03:28:48Z |
| publishDate | 2022-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-73bec63267874935a03e54154dfa4a382022-12-22T00:01:12ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2022-02-01910.3389/fspas.2022.823695823695Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot RegionSolène Lejosne0Bela G. Fejer1Naomi Maruyama2Ludger Scherliess3Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA, United StatesCenter for Atmospheric and Space Sciences, Utah State University, Logan, UT, United StatesLaboratory for Atmospheric and Space Physics, University of Boulder, Boulder, CO, United StatesCenter for Atmospheric and Space Sciences, Utah State University, Logan, UT, United StatesThe “zebra stripes” are drift-periodic structures present in the form of peaks and valleys in energetic (tens to hundreds of keV) electron spectrograms in the Earth’s inner belt and slot region. Their characteristics inform of preceding electric field disturbances. Specifically, their amplitude contains information on the radial transport of trapped particles generated by azimuthal electric field disturbances. We introduce a method to quantify radial transport from the measured amplitude of the zebra stripes, and we apply it to the zebra stripes observed on 16 February 2014. The findings are compared with results from a particle tracing code that leverages an empirical analytical model for the electric field disturbances. The measured amplitude of the zebra stripes indicates that the electric field disturbances transported the trapped population coherently, over radial distances spanning several hundreds to thousands of kilometers. The magnitude of radial transport is shown to depend on angular drift frequency and initial location (equatorial radial distance and magnetic local time) in the disturbance. The model-observation comparison suggests that the timing for electric field variations provided by the model is valid for studying radial transport in the inner belt and slot region. On the other hand, we found discrepancies when comparing radial transport magnitudes. When assuming that radial transport varies as L3, as weakly suggested by the data for set angular drift frequencies, and extrapolating observations to L = 1, the amount of experimental transport obtained is two to three times greater than numerical estimates. Outputs from the standalone version of the Rice Convection Model (RCM) suggests that the electric field disturbances are likely greater than the estimates provided by the empirical model. RCM also supports the idea that radial transport driven by the prompt penetration of magnetospheric convection varies as L3 in the inner belt and slot region.https://www.frontiersin.org/articles/10.3389/fspas.2022.823695/fullradial transportprompt penetration electric fieldsdisturbance electric fieldstrapped particlesEarth’s inner radiation beltvan allen probes |
| spellingShingle | Solène Lejosne Bela G. Fejer Naomi Maruyama Ludger Scherliess Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region Frontiers in Astronomy and Space Sciences radial transport prompt penetration electric fields disturbance electric fields trapped particles Earth’s inner radiation belt van allen probes |
| title | Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region |
| title_full | Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region |
| title_fullStr | Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region |
| title_full_unstemmed | Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region |
| title_short | Radial Transport of Energetic Electrons as Determined From the “Zebra Stripes” Measured in the Earth’s Inner Belt and Slot Region |
| title_sort | radial transport of energetic electrons as determined from the zebra stripes measured in the earth s inner belt and slot region |
| topic | radial transport prompt penetration electric fields disturbance electric fields trapped particles Earth’s inner radiation belt van allen probes |
| url | https://www.frontiersin.org/articles/10.3389/fspas.2022.823695/full |
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