Optical observations geomagnetically conjugate to sprite-producing lightning discharges
Theoretical studies have predicted that large positive cloud-to-ground discharges can trigger a runaway avalanche process of relativistic electrons, forming a geomagnetically trapped electron beam. The beam may undergo pitch angle and energy scattering during its traverse of the Earth's ma...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2005-09-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/23/2231/2005/angeo-23-2231-2005.pdf |
| _version_ | 1818177491604340736 |
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| author | R. A. Marshall U. S. Inan T. Neubert A. Hughes G. Sátori J. Bór A. Collier T. H. Allin |
| author_facet | R. A. Marshall U. S. Inan T. Neubert A. Hughes G. Sátori J. Bór A. Collier T. H. Allin |
| author_sort | R. A. Marshall |
| collection | DOAJ |
| description | Theoretical studies have predicted that large positive
cloud-to-ground discharges can trigger a runaway avalanche process
of relativistic electrons, forming a geomagnetically trapped
electron beam. The beam may undergo pitch angle and energy
scattering during its traverse of the Earth's magnetosphere, with
a small percentage of electrons remaining in the loss cone and
precipitating in the magnetically conjugate atmosphere. In
particular, <i>N<sub>2</sub> 1P</i> and <i>N<sub>2</sub><sup>+</sup>1N</i> optical emissions are
expected to be observable. In July and August 2003, an attempt
was made to detect these optical emissions, called "conjugate
sprites", in correlation with sprite observations in Europe near
<img src="ag-23-2231-img3.gif" border="0">. Sprite observations were made from the
Observatoire du Pic du Midi (OMP) in the French Pyrenées, and
VLF receivers were installed in Europe to detect causative sferics
and ionospheric disturbances associated with sprites. In the
Southern Hemisphere conjugate region, the Wide-angle Array for
Sprite Photometry (WASP) was deployed at the South African
Astronomical Observatory (SAAO), near Sutherland, South Africa, to
observe optical emissions with a field-of-view magnetically
conjugate to the Northern Hemisphere observing region.
Observations at OMP revealed over 130 documented sprites, with
WASP observations covering the conjugate region successfully for
30 of these events. However, no incidences of optical emissions in
the conjugate hemisphere were found. Analysis of the conjugate
optical data from SAAO, along with ELF energy measurements from
Palmer Station, Antarctica, and charge-moment analysis, show that
the lightning events during the course of this experiment likely
had insufficient intensity to create a relativistic beam.<br><br>
<b>Keywords.</b> Ionosphere (Ionsophere-magnetosphere interactions;
Ionospheric disturbances; Instruments and techniques) |
| first_indexed | 2024-12-11T20:32:56Z |
| format | Article |
| id | doaj.art-02c5a8c91b9d40fba9ea653f7573a44e |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-11T20:32:56Z |
| publishDate | 2005-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-02c5a8c91b9d40fba9ea653f7573a44e2022-12-22T00:51:44ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762005-09-01232231223710.5194/angeo-23-2231-2005Optical observations geomagnetically conjugate to sprite-producing lightning dischargesR. A. Marshall0U. S. Inan1T. Neubert2A. Hughes3G. Sátori4J. Bór5A. Collier6T. H. Allin7STARLab, Stanford University, Stanford, CA, USASTARLab, Stanford University, Stanford, CA, USADanish Space Research Institute, Copenhagen, DenmarkUniversity of KwaZulu-Natal, Durban, South AfricaGeodetic and Geophysical Research Institute, Sopron, HungaryGeodetic and Geophysical Research Institute, Sopron, HungaryUniversity of KwaZulu-Natal, Durban, South AfricaDanish Technical University, Lyngby, DenmarkTheoretical studies have predicted that large positive cloud-to-ground discharges can trigger a runaway avalanche process of relativistic electrons, forming a geomagnetically trapped electron beam. The beam may undergo pitch angle and energy scattering during its traverse of the Earth's magnetosphere, with a small percentage of electrons remaining in the loss cone and precipitating in the magnetically conjugate atmosphere. In particular, <i>N<sub>2</sub> 1P</i> and <i>N<sub>2</sub><sup>+</sup>1N</i> optical emissions are expected to be observable. In July and August 2003, an attempt was made to detect these optical emissions, called "conjugate sprites", in correlation with sprite observations in Europe near <img src="ag-23-2231-img3.gif" border="0">. Sprite observations were made from the Observatoire du Pic du Midi (OMP) in the French Pyrenées, and VLF receivers were installed in Europe to detect causative sferics and ionospheric disturbances associated with sprites. In the Southern Hemisphere conjugate region, the Wide-angle Array for Sprite Photometry (WASP) was deployed at the South African Astronomical Observatory (SAAO), near Sutherland, South Africa, to observe optical emissions with a field-of-view magnetically conjugate to the Northern Hemisphere observing region. Observations at OMP revealed over 130 documented sprites, with WASP observations covering the conjugate region successfully for 30 of these events. However, no incidences of optical emissions in the conjugate hemisphere were found. Analysis of the conjugate optical data from SAAO, along with ELF energy measurements from Palmer Station, Antarctica, and charge-moment analysis, show that the lightning events during the course of this experiment likely had insufficient intensity to create a relativistic beam.<br><br> <b>Keywords.</b> Ionosphere (Ionsophere-magnetosphere interactions; Ionospheric disturbances; Instruments and techniques)https://www.ann-geophys.net/23/2231/2005/angeo-23-2231-2005.pdf |
| spellingShingle | R. A. Marshall U. S. Inan T. Neubert A. Hughes G. Sátori J. Bór A. Collier T. H. Allin Optical observations geomagnetically conjugate to sprite-producing lightning discharges Annales Geophysicae |
| title | Optical observations geomagnetically conjugate to sprite-producing lightning discharges |
| title_full | Optical observations geomagnetically conjugate to sprite-producing lightning discharges |
| title_fullStr | Optical observations geomagnetically conjugate to sprite-producing lightning discharges |
| title_full_unstemmed | Optical observations geomagnetically conjugate to sprite-producing lightning discharges |
| title_short | Optical observations geomagnetically conjugate to sprite-producing lightning discharges |
| title_sort | optical observations geomagnetically conjugate to sprite producing lightning discharges |
| url | https://www.ann-geophys.net/23/2231/2005/angeo-23-2231-2005.pdf |
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