SuperDARN observations of ionospheric heater–induced upper hybrid waves

Hughes, John M.; Bristow, W. A.; Parris, Richard; Lundell, E.

doi:10.1029/2003gl018772

Cited by 19 publications

(36 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the enhancement of the Kodiak SuperDARN radar signal is expected to be due to the interaction with UH waves. The first direct detection and observation of UH waves during O-mode heating of the ionosphere at HAARP was reported by Hughes et al [2003]. The HF scattering mode detected by the Kodiak Super-DARN radar during the O-mode heating on 7 August 2012 from 4:30 UT to 5:25 UT is shown in Figure 5.…”

Section: Discrete Ion Gyro-features For F 0 3f Cementioning

confidence: 92%

See 1 more Smart Citation

Ion gyro‐harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro‐harmonic heating

et al. 2013

View full text Add to dashboard Cite

[1] Stimulated electromagnetic emissions (SEEs) are secondary radiation produced during active space experiments in which the ionosphere is actively heated with high power high frequency (HF) ground-based radio transmitters. Recently, there has been significant interest in ion gyro-harmonic structuring the SEE spectrum due to the potential for new diagnostic information available such as electron acceleration and creation of artificial ionization layers. These relatively recently discovered gyro-harmonic spectral features have almost exclusively been studied when the transmitting frequency is near the second electron gyro-harmonic frequency. The first extensive systematic experimental investigations of the possibility of these spectral features for third electron gyro-harmonic heating are provided here. Discrete spectral features shifted from the transmit frequency ordered by harmonics of the ion gyro-frequency were observed for third electron gyro-harmonic heating for the first time at a recent campaign at the High Frequency Active Auroral Research Program (HAARP) facility. These features were also closely correlated with a broader band feature at a larger frequency shift from the transmit frequency known as the downshifted peak (DP). The power threshold of these spectral features was measured, as well as their behavior with heater beam angle, and proximity of the transmit frequency to the third electron gyro-harmonic frequency. Comparisons were also made with similar spectral features observed during second electron gyro-harmonic heating during the same campaign. A theoretical model is provided that interprets these spectral features as resulting from parametric decay instabilities in which the pump field ultimately decays into high frequency upper hybrid/electron Bernstein and low frequency neutralized ion Bernstein IB and/or obliquely propagating ion acoustic waves at the upper hybrid interaction altitude. Coordinated optical and SEE observations were carried out in order to provide a better understanding of electron acceleration and precipitation processes. Optical emissions were observed associated with SEE gyro-harmonic features for pump heating near the second electron gyro-harmonic during the campaign. The observations affirm strong correlation between the gyro-structures and the pump-induced optical emissions.

show abstract

Section: Discrete Ion Gyro-features For F 0 3f Cementioning

confidence: 92%

“…It has been shown that Langmuir waves propagate along B while UH waves propagate normal to B [Hughes et al, 2003]. Therefore, the enhancement of the Kodiak SuperDARN radar signal is expected to be due to the interaction with UH waves.…”

Section: Discrete Ion Gyro-features For F 0 3f Cementioning

confidence: 99%

Ion gyro‐harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro‐harmonic heating

et al. 2013

View full text Add to dashboard Cite

show abstract

“…HAARP is currently the only ionospheric heater capable of selecting a pump frequency suitable for passing through the second gyro-harmonic of almost any nighttime ionosphere. On 25 February 2004 an experiment was performed, which attempted to pass through the third and second gyro-harmonic frequencies for Kodiak radar (SuperDARN) plasma-line (f radar +f heater ) observations (Hughes et al, 2003). Simultaneously, optical measurements were made by different filtered camera systems, ranging from all-sky to telescopic, and a photometer.…”

Section: Results and Analysismentioning

confidence: 99%

Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic

et al. 2005

View full text Add to dashboard Cite

Abstract. 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 gyroharmonics. 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.

show abstract

“…Stubbe et al, 1982;Hedberg et al, 1983), SPEAR (e.g. Robinson et al, 2006), and at the emerging HAARP site near Gakona, Alaska (Hughes et al, 2003). Observations at different radar and heating frequencies and at different latitudes and pointing directions have spurred controversy and accelerated the development of comprehensive ionospheric modification theories.…”

Section: Subsequent Observations Of Artificially Induced Fais Werementioning

confidence: 99%

30 MHz radar observations of artificial E region field-aligned plasma irregularities

Hysell

2008

Ann. Geophys.

View full text Add to dashboard Cite

Abstract. Artificial E region field aligned irregularities (FAIs) have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid-and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

show abstract

SuperDARN observations of ionospheric heater–induced upper hybrid waves

Cited by 19 publications

References 17 publications

Ion gyro‐harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro‐harmonic heating

Ion gyro‐harmonic structuring in the stimulated radiation spectrum and optical emissions during electron gyro‐harmonic heating

Artificial optical emissions at HAARP for pump frequencies near the third and second electron gyro-harmonic

30 MHz radar observations of artificial E region field-aligned plasma irregularities

Contact Info

Product

Resources

About