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Temporal evolution of pump beam self-focusing at the High-Frequency Active Auroral Research Program

By Mike J. Kosch, T. Pedersen, E. Mishin, M. Starks, E. Gerken-Kendall, D. Sentman, S. Oyama and B. Watkins


On 4 February 2005 the High-Frequency Active Auroral Research Program (HAARP) facility was operated at 2.85 MHz to produce artificial optical emissions in the ionosphere while passing through the second electron gyroharmonic. All-sky optical recordings were performed with 15 s integration, alternating between 557.7 and 630 nm. We report the first optical observations showing the temporal evolution of large-scale pump wave self-focusing in the magnetic zenith, observed in the 557.7 nm images. These clearly show that the maximum intensity was not reached after 15 s of pumping, which is unexpected since the emission delay time is <1 s, and that the optical signature had intensified in a much smaller region within the beam after 45 s of pumping. In addition, adjacent regions within the beam lost intensity. Radar measurements indicate a plasma depletion of ∼1% near the HF reflection altitude. Ray tracing of the pump wave through the plasma depletion region, which forms a concave reflecting radio wave mirror, reproduces the optical spatial morphology. A radio wave flux density gain of up to ∼30 dB may occur. In addition, the ray trace is consistent with the observed artificial optical emissions for critical plasma frequencies down to ∼0.5 MHz below the pump frequency

Year: 2007
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Provided by: Lancaster E-Prints

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  4. (2005). Artificial optical emissions at HAARP for pump frequencies near the third and second gyroharmonic, doi
  5. (2007). Coordinated optical and radar observations of ionospheric pumping for a frequency pass through the second electron gyro-harmonic at HAARP, doi
  6. (1995). Density depletions at the 10-m scale induced by the Arecibo heater, doi
  7. (1997). Evolution of subkilometer scale ionospheric irregularities generated by high-power HF waves, doi
  8. (1985). Experimental results from the HERO project: In situ measurements of ionospheric modifications using sounding rockets, doi
  9. (1983). Fejer doi
  10. (1996). First EISCAT observations of the modification of F-region electron temperatures during RF heating at harmonics of the electron gyro frequency, doi
  11. (2001). First observations of HF heaterproduced airglow at the High Frequency Active Auroral Research Program facility: Thermal excitation and spatial structuring, doi
  12. (2001). First tomographic estimate of volume distribution of HF-pump enhanced airglow emission, doi
  13. (1999). Hagfors (2002a), The high-latitude artificial aurora of 21
  14. Hagfors (2002b), High-latitude pump-induced optical emissions for frequencies close to the third electron gyro-harmonic, doi
  15. (2006). Heater-induced altitude descent of the EISCAT UHF ion-line overshoot: Observations and modeling, doi
  16. (1974). HF phased array observations of heater-induced spread-F, doi
  17. (2005). HF-induced airglow at magnetic zenith: theoretical considerations, doi
  18. (2003). High latitude artificial aurora from HEATING: A unique phenomenon?, paper presented at 28th Annual European Meeting on Atmospheric Studies by Optical Methods, Sodankyla Geophys. Obs.,
  19. (2000). Highlatitude HF-induced airglow displaced equatorwards of the pump beam, doi
  20. (2006). Imaging HF-induced large-scale irregularities above HAARP, doi
  21. (2003). Ionospheric electron heating, optical emissions and striations induced by powerful HF radio waves at high latitudes: Aspect angle dependence, doi
  22. (1979). Ionospheric modification and parametric instabilities, doi
  23. (2005). Ionospheric modification at twice the electron cyclotron frequency, doi
  24. (1987). Large F region electron-temperature enhancements generated by high-power HF radio waves, doi
  25. (2002). Magnetic zenith effect in ionospheric modifications, doi
  26. (2003). Magnetic zenith enhancement of HF radio-induced airglow production at HAARP, doi
  27. (2002). Nearly simultaneous images of HF-pump enhanced airglow at 6300 A and 5577 doi
  28. (2001). Nonlinear structuring and southward shift of a strongly heated region in ionospheric modification, doi
  29. (1999). Nonlinear structuring of the ionosphere modified by powerful radio waves at low latitudes, doi
  30. (1988). Observations of ionospheric cavities generated by high-power radio waves, doi
  31. On the onset of HFinduced airglow at HAARP,
  32. (2006). Persistent enhancement of the HF pump-induced plasma line measured with a UHF diagnostic radar at HAARP, doi
  33. (1974). Production of ionospheric striations by self-focusing of intense radio waves, doi
  34. (1992). Resolution of temporal and spatial ambiguities of intensity variations within pulsating aurorae, doi
  35. (2006). Saturation and hysteresis effects in ionospheric modification experiments observed by the CUTLASS and EISCAT radars, doi
  36. (1999). SELF-FOCUSING 8o f9 A08304Bra ¨ndstro
  37. (1981). Self-focusing of radio waves in an underdense ionosphere, doi
  38. Sheerin (1988a), Spatial and temporal evolution of 630.0 nm airglow enhancements during ionospheric heating experiments, doi
  39. (2000). Simultaneous measurements of high-frequency pump-enhanced airglow and ionospheric temperatures at auroral latitudes, Adv. Polar Upper Atmos.
  40. (1970). Some ionosonde observations of ionosphere modification by very high power, high frequency ground-based transmission, doi
  41. (2004). SuperDARN observations of spectral enhancements excited during an ionospheric heating experiment, doi
  42. Tepley (1988b), Artificial airglow excited by high-power radio waves, doi
  43. (1995). The ionospheric focused heating experiment, doi
  44. (1996). The self-focusing instability in the presence of density irregularities in the ionosphere, doi
  45. (1987). The theory of ionospheric focused heating, doi
  46. (1998). The thermal self-focussing instability near the critical surface in the high-latitude ionosphere, doi
  47. (1988). Thermal response of the F region ionosphere for conditions of large HF-induced electron-temperature enhancements, doi
  48. Viggiano (2004a), Stormtime subauroral density troughs: Ion-molecule kinetics effects, doi
  49. (1982). Wide band attenuation of radio waves caused by powerful HF waves: Saturation and dependence on ionospheric variability, doi

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