Determination of the electron temperature in the modified ionosphere over HAARP using the HF pumped Stimulated Brillouin Scatter (SBS) emission lines

Bernhardt, P. A.; Selcher, C. A.; Lehmberg, R. H.; Rodriguez, Serafin; Thomason, J. F.; McCarrick, M.; Frazer, G.J.

doi:10.5194/angeo-27-4409-2009

Cited by 54 publications

(85 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Such electric field amplitudes in the upper hybrid layer have been estimated to be in the range of 10 V/m by Samimi et al [2012b] which is relevant to this investigation. They have also been estimated to be in the range of greater than 100 V/m by Bernhardt et al [2009] at the reflection altitude.…”

Section: Theory and Resultsmentioning

confidence: 99%

“…The spectra then immediately showed downshifted and upshifted emissions at harmonics of f ci as well as ion acoustic IA emission lines near 10 Hz. The discrete structures are attributed to SIBS instability and the IA emission lines are due to the Magnetized Stimulated Brillouin Scatter (MSBS) process [Norin et al, 2009;Bernhardt et al, 2009Bernhardt et al, , 2010. Figure 1 shows four snapshots of high resolution power spectrum for P heater = 0.1 MW, P heater = 0.7 MW, P heater = 2 MW, and P heater = 3.6 MW.…”

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

confidence: 99%

“…The structures upshifted from the heater frequency correspond to the 2nd to 11th harmonics of the ion gyrofrequency, respectively. A distinct emission line appears in the spectra near 62 Hz for full power which is most likely the electrostatic ion cyclotron (EIC) mode generated through MSBS [Bernhardt et al, 2009 and. Therefore, the IA line (MSBS process), ion gyro-harmonic lines (SIBS), and EIC line (MSBS process) have the thresholds of 0.4 MW (ERP 110 MW), 0.7 MW (ERP 190 MW) and 2.9 MW (ERP 800 MW), respectively.…”

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

confidence: 99%

“…The direct parametric decay instability can be distinguished by strong SEE spectral sidebands. Magnetized stimulated Brillouin scatter (MSBS) which involves decay of the EM pump wave into ion acoustic IA or electrostatic ion cyclotron (EIC) and a scattered EM wave is an example of the direct conversion [Norin et al, 2009;Bernhardt et al, 2009Bernhardt et al, , 2010. The other possible scenario is the conversion of the EM wave first to a high frequency ES wave and irregularities through the oscillating two stream instability (OTSI) [Dysthe et al, 1983;Huang and Kuo, 1995].…”

Section: Introductionmentioning

confidence: 99%

“…IA and EIC mode excitation through the MSBS instability can be used to estimate the electron temperature and as ion mass spectrometers to determine the composition of the E and F layers, respectively [Bernhardt et al, 2009[Bernhardt et al, , 2010. It also has been shown that the spatial scale of striations involved in the formation of the DM and broad upshifted maximum (BUM) can be estimated by measuring the decay rate of the peak intensity of the DM and BUM [Norin et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

et al. 2013

Self Cite

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: Theory and Resultsmentioning

confidence: 99%

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

confidence: 99%

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

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

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

et al. 2014

Self Cite

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

Investigation of ionospheric stimulated Brillouin scatter generated at pump frequencies near electron gyroharmonics

et al. 2013

Self Cite

View full text Add to dashboard Cite

[1] Stimulated Electromagnetic Emissions (SEEs), secondary electromagnetic waves excited by high power electromagnetic waves transmitted into the ionosphere, produced by the Magnetized Stimulated Brillouin Scatter (MSBS) process are investigated. Data from four recent research campaigns at the High Frequency Active Auroral Research Program (HAARP) facility is presented in this work. These experiments have provided additional quantitative interpretation of the SEE spectrum produced by MSBS to yield diagnostic measurements of the electron temperature and ion composition in the heated ionosphere. SEE spectral emission lines corresponding to ion acoustic (IA) and electrostatic ion cyclotron (EIC) mode excitation were observed with a shift in frequency up to a few tens of Hz from the pump frequency for heating near the third harmonic of the electron gyrofrequency 3f ce . The threshold of each emission line has been measured by changing the pump wave power. The excitation threshold of IA and EIC emission lines originating at the reflection and upper hybrid altitudes is measured for various beam angles relative to the magnetic field. Variation of strength of MSBS emission lines with pump frequency relative to 3f ce and 4f ce is also studied. A full wave solution has been used to estimate the amplitude of the electric field at the interaction altitude. The estimated instability threshold using the theoretical model is compared with the threshold of MSBS lines in the experiment and possible diagnostic information for the background ionospheric plasma is discussed. Simultaneous formation of artificial field-aligned irregularities (FAIs) and suppression of the MSBS process is investigated. This technique can be used to estimate the growth time of artificial FAIs which may result in determination of plasma waves and physical process involved in the formation of FAIs.Citation: Mahmoudian, A., W. A. Scales, P. A. Bernhardt, H. Fu, S. J. Briczinski, and M. J. , Investigation of ionospheric stimulated Brillouin scatter generated at pump frequencies near electron gyroharmonics, Radio Sci., 48,[685][686][687][688][689][690][691][692][693][694][695][696][697]

show abstract

Determination of the electron temperature in the modified ionosphere over HAARP using the HF pumped Stimulated Brillouin Scatter (SBS) emission lines

Cited by 54 publications

References 19 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

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

Investigation of ionospheric stimulated Brillouin scatter generated at pump frequencies near electron gyroharmonics

Contact Info

Product

Resources

About