Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora
International audience [1] We present simultaneous measurements of dayside diffuse aurora and whistler-mode waves made by the South Pole all-sky imager and two of the THEMIS spacecraft. We found a high correlation between the diffuse aurora intensity at 557.7 nm near the footprint latitudes of THEMI...
Published in: | Journal of Geophysical Research: Space Physics |
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Online Access: | https://hal.science/hal-01552044 https://doi.org/10.1029/2012JA018242 |
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ftuniparissaclay:oai:HAL:hal-01552044v1 2024-05-19T07:48:41+00:00 Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora Nishimura, Y. Bortnik, J. Li, W. Thome, R.M. Ni, B. Lyons, L.R. Angelopoulos, V. Ebihara, Y. Bonnell, J. W. Le Contel, Olivier Auster, U. Laboratoire de Physique des Plasmas (LPP) Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) 2013 https://hal.science/hal-01552044 https://doi.org/10.1029/2012JA018242 en eng HAL CCSD American Geophysical Union/Wiley info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JA018242 hal-01552044 https://hal.science/hal-01552044 doi:10.1029/2012JA018242 ISSN: 2169-9380 EISSN: 2169-9402 Journal of Geophysical Research Space Physics https://hal.science/hal-01552044 Journal of Geophysical Research Space Physics, 2013, 118 (2), pp.664-673. ⟨10.1029/2012JA018242⟩ [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] info:eu-repo/semantics/article Journal articles 2013 ftuniparissaclay https://doi.org/10.1029/2012JA018242 2024-04-22T17:44:10Z International audience [1] We present simultaneous measurements of dayside diffuse aurora and whistler-mode waves made by the South Pole all-sky imager and two of the THEMIS spacecraft. We found a high correlation between the diffuse aurora intensity at 557.7 nm near the footprint latitudes of THEMIS and whistler-mode wave intensity measured on board. The power in other wave modes was negligibly small in most cases, indicating that the dayside diffuse aurora is driven by precipitating energetic electrons resonating with whistler-mode waves. The high correlation over a wide L* range (6 < L* < 11) further allowed us to magnetically link the wave and magnetospheric plasma distributions with the auroral patterns. Two distinct regions of whistler-mode waves and ambient plasma density were found outside the plasmasphere near the equator: (1) intense waves in a smooth, low density and (2) moderate waves with enhanced and fluctuating density. The whistler-mode wave intensity in the fluctuating plasma density region is positively correlated with the ambient density variations. The corresponding auroral images show an azimuthally elongated diffuse auroral band on the field lines connected to the low density region, as opposed to a structured diffuse aurora on the fluctuating density field lines. Each structured diffuse auroral patch was stable for a few tens of minutes and slowly drifted azimuthally. The high correlation of waves and auroras indicates that the structured diffuse auroral pattern reflects the spatial distribution of whistler-mode waves and ambient plasma density in space. The enhanced density measured by the spacecraft is quasi-spatial and contributes to enhanced growth of whistler-mode waves. Article in Journal/Newspaper South pole Archives ouvertes de Paris-Saclay Journal of Geophysical Research: Space Physics 118 2 664 673 |
institution |
Open Polar |
collection |
Archives ouvertes de Paris-Saclay |
op_collection_id |
ftuniparissaclay |
language |
English |
topic |
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] |
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[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Nishimura, Y. Bortnik, J. Li, W. Thome, R.M. Ni, B. Lyons, L.R. Angelopoulos, V. Ebihara, Y. Bonnell, J. W. Le Contel, Olivier Auster, U. Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
topic_facet |
[PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph] [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] |
description |
International audience [1] We present simultaneous measurements of dayside diffuse aurora and whistler-mode waves made by the South Pole all-sky imager and two of the THEMIS spacecraft. We found a high correlation between the diffuse aurora intensity at 557.7 nm near the footprint latitudes of THEMIS and whistler-mode wave intensity measured on board. The power in other wave modes was negligibly small in most cases, indicating that the dayside diffuse aurora is driven by precipitating energetic electrons resonating with whistler-mode waves. The high correlation over a wide L* range (6 < L* < 11) further allowed us to magnetically link the wave and magnetospheric plasma distributions with the auroral patterns. Two distinct regions of whistler-mode waves and ambient plasma density were found outside the plasmasphere near the equator: (1) intense waves in a smooth, low density and (2) moderate waves with enhanced and fluctuating density. The whistler-mode wave intensity in the fluctuating plasma density region is positively correlated with the ambient density variations. The corresponding auroral images show an azimuthally elongated diffuse auroral band on the field lines connected to the low density region, as opposed to a structured diffuse aurora on the fluctuating density field lines. Each structured diffuse auroral patch was stable for a few tens of minutes and slowly drifted azimuthally. The high correlation of waves and auroras indicates that the structured diffuse auroral pattern reflects the spatial distribution of whistler-mode waves and ambient plasma density in space. The enhanced density measured by the spacecraft is quasi-spatial and contributes to enhanced growth of whistler-mode waves. |
author2 |
Laboratoire de Physique des Plasmas (LPP) Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Nishimura, Y. Bortnik, J. Li, W. Thome, R.M. Ni, B. Lyons, L.R. Angelopoulos, V. Ebihara, Y. Bonnell, J. W. Le Contel, Olivier Auster, U. |
author_facet |
Nishimura, Y. Bortnik, J. Li, W. Thome, R.M. Ni, B. Lyons, L.R. Angelopoulos, V. Ebihara, Y. Bonnell, J. W. Le Contel, Olivier Auster, U. |
author_sort |
Nishimura, Y. |
title |
Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
title_short |
Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
title_full |
Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
title_fullStr |
Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
title_full_unstemmed |
Structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
title_sort |
structures of dayside whistler-mode waves deduced from conjugate diffuse aurora |
publisher |
HAL CCSD |
publishDate |
2013 |
url |
https://hal.science/hal-01552044 https://doi.org/10.1029/2012JA018242 |
genre |
South pole |
genre_facet |
South pole |
op_source |
ISSN: 2169-9380 EISSN: 2169-9402 Journal of Geophysical Research Space Physics https://hal.science/hal-01552044 Journal of Geophysical Research Space Physics, 2013, 118 (2), pp.664-673. ⟨10.1029/2012JA018242⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/2012JA018242 hal-01552044 https://hal.science/hal-01552044 doi:10.1029/2012JA018242 |
op_doi |
https://doi.org/10.1029/2012JA018242 |
container_title |
Journal of Geophysical Research: Space Physics |
container_volume |
118 |
container_issue |
2 |
container_start_page |
664 |
op_container_end_page |
673 |
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1799466998581690368 |