Coordinated optical and radar observations of ionospheric pumping for a frequency pass through the second electron gyroharmonic at HAARP

Kosch, M. J.; Pedersen, T. R.; Mishin, E. V.; Oyama, Shin‐ichiro; Hughes, John M.; Senior, Andrew; Watkins, B. J.; Bristow, B.

doi:10.1029/2006ja012146

Cited by 34 publications

(62 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Heat conduction along the magnetic field line depletes the plasma density, permitting the pump wave to propagate beyond the original reflection altitude into the over dense plasma. This is consistent with observations of strong 10-m scale production of striations when pumping the ionospheric F-layer above the second gyroharmonic [Kosch et al, 2007]. [Oyama et al, 2006] facilities.…”

Section: Introductionsupporting

confidence: 80%

“…The intrinsic noise level of the optical data is <1 R. The 557.7 nm optical intensity in the magnetic zenith, peaking at $11 R, is approximately double that averaged KOSCH ET AL. : PUMP BEAM SELF-FOCUSING over much of the beam, peaking at $7 R. The 630 nm emission is similar (not shown), peaking at $58 R in the magnetic zenith and $24 R over much of the beam [Kosch et al, 2007]. Clearly, the optical emissions are enhanced during the O-mode pump pulses.…”

Section: Resultsmentioning

confidence: 63%

“…[Oyama et al, 2006] facilities. These results are reported by Kosch et al [2007]. The colocated Digisonde provided ionospheric density profiles every 2 min in the range 1 -6 MHz.…”

Section: Introductionmentioning

confidence: 60%

“…Striations can be generated at very low pump powers (<4 MW effective radiated power) [Wright et al, 2006], hence upper-hybrid resonance is rather easily stimulated. Strong production of striations has been observed for pump frequencies above the second electron gyroharmonic ($2.85 MHz in the F-layer) [Kosch et al, 2007]. When pumping occurs outside the so-called Spitze cone, zenith angle $6°at EISCAT and $8°at HAARP, the pump waves will refract down below the nominal HF reflection altitude [e.g., Kosch et al, 2002a] whilst propa-gating away horizontally from the source.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

et al. 2007

Self Cite

View full text Add to dashboard Cite

[1] 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 selffocusing 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.

show abstract

Section: Introductionsupporting

confidence: 80%

Section: Resultsmentioning

confidence: 63%

“…[Oyama et al, 2006] facilities. These results are reported by Kosch et al [2007]. The colocated Digisonde provided ionospheric density profiles every 2 min in the range 1 -6 MHz.…”

Section: Introductionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

et al. 2007

Self Cite

View full text Add to dashboard Cite

show abstract

“…[2] Use of high frequency heating experiments has been extended in recent years as a useful methodology for plasma physicists wishing to remotely study the properties and behavior of the ionosphere as well as nonlinear plasma processes [Hysell and Nossa, 2009;Kosch et al, 2007;Pedersen and Gerken, 2005;Pedersen et al, 2010]. This technique has also been used extensively to investigate the charged dust layers in the mesosphere [Chilson et al, 2000;Havnes et al, 2003;Mahmoudian et al, 2011;Mahmoudian and Scales, 2012].…”

Section: Introductionmentioning

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

[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

Ion gyroharmonic structures in stimulated radiation during second electron gyroharmonic heating: 2. Simulations

et al. 2014

View full text Add to dashboard Cite

Characteristics of the Stimulated Electromagnetic Emission (SEE) spectrum recorded during ionospheric heating near the second electron gyroharmonic frequency, 2fce, have attracted attention due to their possible connection to artificially generated airglow and artificial ionospheric layers. Two newly discovered SEE spectral features within 1 kHz frequency shift relative to the pump frequency are (1) discrete narrowband structures ordered by the local ion gyrofrequency involving parametric decay of the pump field into upper hybrid/electron Bernstein (UH/EB) and ion Bernstein (IB) waves and (2) broadband structures that maximize around 500 Hz downshifted relative to the pump frequency involving parametric decay of the pump field into upper hybrid/electron Bernstein and oblique ion acoustic (IA) waves [Samimi et al., 2013]. In this paper, a two‐dimensional particle‐in‐cell Monte Carlo Collision computational model is employed in order to consider nonlinear aspects such as (1) electron acceleration through wave‐particle interaction, (2) more complex nonlinear wave‐wave processes, and (3) temporal evolution of irregularities through nonlinear saturation. The simulation results show that the IB‐associated parametric decay is primarily associated with electron acceleration perpendicular to the geomagnetic field. More gyroharmonic lines are typically associated with more electron acceleration. Electron acceleration is reduced when the pump frequency is sufficiently close to 2fce. The IA‐associated parametric decay instability is primarily associated with electron tail heating along the magnetic field and electron acceleration is reduced when the pump frequency is sufficiently close to 2fce. Characteristics of caviton collapse behavior become prevalent in this case. Results are discussed within the context of some recent experimental observations.

show abstract

Coordinated optical and radar observations of ionospheric pumping for a frequency pass through the second electron gyroharmonic at HAARP

Cited by 34 publications

References 69 publications

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

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

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

Ion gyroharmonic structures in stimulated radiation during second electron gyroharmonic heating: 2. Simulations

Contact Info

Product

Resources

About