On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt
We performed a statistical study on the correlation between electromagnetic Ultra Low Frequency (ULF) waves and the evolution of relativistic electron fluxes in the outer radiation belt for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"...
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| author | Christopher Lara Victor A. Pinto Javier Silva Bea Zenteno-Quinteros Pablo S. Moya |
| author_facet | Christopher Lara Victor A. Pinto Javier Silva Bea Zenteno-Quinteros Pablo S. Moya |
| author_sort | Christopher Lara |
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| description | We performed a statistical study on the correlation between electromagnetic Ultra Low Frequency (ULF) waves and the evolution of relativistic electron fluxes in the outer radiation belt for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.1</mn><mo><</mo><msup><mi>L</mi><mo>∗</mo></msup><mo><</mo><mn>6.0</mn></mrow></semantics></math></inline-formula> during 101 geomagnetic storms that occurred between January 2013 and November 2018. We used the Van Allen Probes MagEIS and REPT instruments to study electron fluxes from 0.47 MeV to 5.2 MeV, and we utilized magnetic field data from EMFISIS to calculate magnetic field fluctuations parallel and perpendicular to the background magnetic field direction and obtain the ULF integrated power between 1 mHz and 10 mHz. We analyzed the data during the following three different time intervals: the main phase, the recovery phase, and the entire storm. We computed the Pearson’s correlation coefficient and mutual information score between the ratio of fluxes before and after each given phase and the total integrated ULF power during the same time interval. Our results show a significant correlation between ULF wave power and changes in fluxes of hundreds of keV electrons during the main phase of the storms and for MeV electrons during the recovery phase of the storms. By studying fluxes at independent <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>L</mi><mo>∗</mo></msup></semantics></math></inline-formula>, the largest correlations correspond to changes in fluxes before and after the entire storm and ULF fluctuations parallel to the field, especially for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>L</mi><mo>∗</mo></msup><mo><</mo><mn>4.6</mn></mrow></semantics></math></inline-formula>. We evaluated the drift resonance frequency for azimuthal wavenumber <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>≤</mo><mi>m</mi><mo>≤</mo><mn>10</mn></mrow></semantics></math></inline-formula> and found that for all considered energies and frequencies, the drift resonance with Pc5 ULF waves may occur in our region of study, which is consistent with the statistical results. |
| format | Article |
| id | doaj-art-cfdc01ee8a8f436dbbfa6908449e7042 |
| institution | DOAJ |
| issn | 2218-1997 |
| language | English |
| publishDate | 2025-05-01 |
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| spelling | doaj-art-cfdc01ee8a8f436dbbfa6908449e70422025-08-20T03:12:09ZengMDPI AGUniverse2218-19972025-05-0111515110.3390/universe11050151On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation BeltChristopher Lara0Victor A. Pinto1Javier Silva2Bea Zenteno-Quinteros3Pablo S. Moya4Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago 8460000, ChileDepartamento de Fisica, Universidad de Santiago de Chile, Santiago 9170020, ChileDepartamento de Fisica, Universidad de Santiago de Chile, Santiago 9170020, ChileDepartamento de Fisica, Universidad de Santiago de Chile, Santiago 9170020, ChileDepartamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago 8460000, ChileWe performed a statistical study on the correlation between electromagnetic Ultra Low Frequency (ULF) waves and the evolution of relativistic electron fluxes in the outer radiation belt for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.1</mn><mo><</mo><msup><mi>L</mi><mo>∗</mo></msup><mo><</mo><mn>6.0</mn></mrow></semantics></math></inline-formula> during 101 geomagnetic storms that occurred between January 2013 and November 2018. We used the Van Allen Probes MagEIS and REPT instruments to study electron fluxes from 0.47 MeV to 5.2 MeV, and we utilized magnetic field data from EMFISIS to calculate magnetic field fluctuations parallel and perpendicular to the background magnetic field direction and obtain the ULF integrated power between 1 mHz and 10 mHz. We analyzed the data during the following three different time intervals: the main phase, the recovery phase, and the entire storm. We computed the Pearson’s correlation coefficient and mutual information score between the ratio of fluxes before and after each given phase and the total integrated ULF power during the same time interval. Our results show a significant correlation between ULF wave power and changes in fluxes of hundreds of keV electrons during the main phase of the storms and for MeV electrons during the recovery phase of the storms. By studying fluxes at independent <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mi>L</mi><mo>∗</mo></msup></semantics></math></inline-formula>, the largest correlations correspond to changes in fluxes before and after the entire storm and ULF fluctuations parallel to the field, especially for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi>L</mi><mo>∗</mo></msup><mo><</mo><mn>4.6</mn></mrow></semantics></math></inline-formula>. We evaluated the drift resonance frequency for azimuthal wavenumber <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>≤</mo><mi>m</mi><mo>≤</mo><mn>10</mn></mrow></semantics></math></inline-formula> and found that for all considered energies and frequencies, the drift resonance with Pc5 ULF waves may occur in our region of study, which is consistent with the statistical results.https://www.mdpi.com/2218-1997/11/5/151ULF wavesgeomagnetic stormsrelativistic electronsVan Allen Probes |
| spellingShingle | Christopher Lara Victor A. Pinto Javier Silva Bea Zenteno-Quinteros Pablo S. Moya On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt Universe ULF waves geomagnetic storms relativistic electrons Van Allen Probes |
| title | On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt |
| title_full | On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt |
| title_fullStr | On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt |
| title_full_unstemmed | On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt |
| title_short | On the Relationship Between ULF Wave Power and Changes of Relativistic Electron Fluxes in the Outer Radiation Belt |
| title_sort | on the relationship between ulf wave power and changes of relativistic electron fluxes in the outer radiation belt |
| topic | ULF waves geomagnetic storms relativistic electrons Van Allen Probes |
| url | https://www.mdpi.com/2218-1997/11/5/151 |
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