Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic
High-power high-frequency radio waves beamed into the ionosphere cause plasma turbulence, which can accelerate electrons. These electrons collide with the F-layer neutral oxygen causing artificial optical emissions identical to natural aurora. Pumping at electron gyro-harmonic frequencies has sp...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2005-07-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/23/1585/2005/angeo-23-1585-2005.pdf |
| _version_ | 1819169318455214080 |
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| author | M. J. Kosch M. J. Kosch M. J. Kosch T. Pedersen J. Hughes R. Marshall E. Gerken A. Senior D. Sentman M. McCarrick F. T. Djuth |
| author_facet | M. J. Kosch M. J. Kosch M. J. Kosch T. Pedersen J. Hughes R. Marshall E. Gerken A. Senior D. Sentman M. McCarrick F. T. Djuth |
| author_sort | M. J. Kosch |
| collection | DOAJ |
| description | High-power high-frequency radio waves beamed into the ionosphere cause
plasma turbulence, which can accelerate electrons. These electrons collide
with the F-layer neutral oxygen causing artificial optical emissions
identical to natural aurora. Pumping at electron gyro-harmonic frequencies
has special significance as many phenomena change their character. In
particular, artificial optical emissions become strongly reduced for the
third and higher gyro-harmonics. The High frequency Active Auroral Research
Program (HAARP) facility is unique in that it can select a frequency near
the second gyro-harmonic. On 25 February 2004, HAARP was operated near the
third and passed through the second gyro-harmonic for the first time in a
weakening ionosphere. Two novel observations are: firstly, a strong
enhancement of the artificial optical emission intensity near the second
gyro-harmonic, which is opposite to higher gyro-harmonics; secondly, the
optical enhancement maximum occurs for frequencies just above the second
gyro-harmonic. We provide the first experimental evidence for these effects,
which have been predicted theoretically. In addition, irregular optical
structures were created when the pump frequency was above the ionospheric
critical frequency.<p><b>Keywords.</b> Active experiments – Auroral ionosphere –
Wave-particle interactions |
| first_indexed | 2024-12-22T19:17:36Z |
| format | Article |
| id | doaj.art-6d33c92b85a548d1b2a215d3fe32dfa4 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-22T19:17:36Z |
| publishDate | 2005-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-6d33c92b85a548d1b2a215d3fe32dfa42022-12-21T18:15:28ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762005-07-01231585159210.5194/angeo-23-1585-2005Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonicM. J. Kosch0M. J. Kosch1M. J. Kosch2T. Pedersen3J. Hughes4R. Marshall5E. Gerken6A. Senior7D. Sentman8M. McCarrick9F. T. Djuth10Honorary Research Fellow, University of Kwazulu-Natal, Durban, South AfricaCommunication Systems, Lancaster University, Lancaster, UKSpace Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB, Massachusetts, USASpace Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB, Massachusetts, USAGeophysical Institute, University of Alaska, Fairbanks, USASTARLab, Stanford University, Stanford CA, USADept. Electrical & Computer Engineering, Cornell University, Ithaca NY, USACommunication Systems, Lancaster University, Lancaster, UKGeophysical Institute, University of Alaska, Fairbanks, USAAdvanced Power Technologies, Washington D.C., USAGeospace Research, El Segundo CA, USAHigh-power high-frequency radio waves beamed into the ionosphere cause plasma turbulence, which can accelerate electrons. These electrons collide with the F-layer neutral oxygen causing artificial optical emissions identical to natural aurora. Pumping at electron gyro-harmonic frequencies has special significance as many phenomena change their character. In particular, artificial optical emissions become strongly reduced for the third and higher gyro-harmonics. The High frequency Active Auroral Research Program (HAARP) facility is unique in that it can select a frequency near the second gyro-harmonic. On 25 February 2004, HAARP was operated near the third and passed through the second gyro-harmonic for the first time in a weakening ionosphere. Two novel observations are: firstly, a strong enhancement of the artificial optical emission intensity near the second gyro-harmonic, which is opposite to higher gyro-harmonics; secondly, the optical enhancement maximum occurs for frequencies just above the second gyro-harmonic. We provide the first experimental evidence for these effects, which have been predicted theoretically. In addition, irregular optical structures were created when the pump frequency was above the ionospheric critical frequency.<p><b>Keywords.</b> Active experiments – Auroral ionosphere – Wave-particle interactionshttps://www.ann-geophys.net/23/1585/2005/angeo-23-1585-2005.pdf |
| spellingShingle | M. J. Kosch M. J. Kosch M. J. Kosch T. Pedersen J. Hughes R. Marshall E. Gerken A. Senior D. Sentman M. McCarrick F. T. Djuth Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic Annales Geophysicae |
| title | Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic |
| title_full | Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic |
| title_fullStr | Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic |
| title_full_unstemmed | Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic |
| title_short | Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic |
| title_sort | artificial optical emissions at haarp for pump frequencies near the third and second electron gyro harmonic |
| url | https://www.ann-geophys.net/23/1585/2005/angeo-23-1585-2005.pdf |
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