Plasma modifications induced by an X-mode HF heater wave in the high latitude F region of the ionosphere

Blagoveshchenskaya, N. F.; Борисова, Т. Д.; Yeoman, T. K.; Rietveld, M. T.; Häggström, Ingemar; Ivanova, I. P.

doi:10.1016/j.jastp.2012.10.001

Cited by 28 publications

(25 citation statements)

References 35 publications

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“…The growing body of X‐mode experiments at the EISCAT (European Incoherent Scatter) Scientific Association HF heating facility with the use of various multi‐instrument diagnostics showed that extraordinary (X‐mode) powerful HF radio waves are capable of producing a strong modification of the high latitudinal ionospheric F region, including the generation of the artificial field‐aligned irregularities (FAIs) (Blagoveshchenskaya, Borisova, Yeoman, Rietveld, ; Blagoveshchenskaya, Borisova, Yeoman, Rietveld, Ivanova, et al, ; Blagoveshchenskaya et al, ), optical emissions at red (630 nm) and green (557.7 nm) lines (Blagoveshchenskaya et al, ), and various spectral components in the narrowband stimulated electromagnetic emission spectra (Blagoveshchenskaya et al, ). Considerable study has been given to the HF‐enhanced ion and plasma lines (HFILs and HFPLs) from the EISCAT UHF incoherent scatter radar spectra excited under X‐mode heating, which are the signatures of the ion acoustic (IA) and Langmuir (L) electrostatic waves (Blagoveshchenskaya et al, , ).…”

Section: Introductionmentioning

confidence: 99%

Comment on “Parametric Instability Induced by X‐Mode Wave Heating at EISCAT” by Wang et al. (2016)

2017

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In their recent article Wang et al. (2016) analyzed observations from EISCAT (European Incoherent Scatter) Scientific Association Russian X‐mode heating experiments and claimed to explain the potential mechanisms for the parametric decay instability (PDI) and oscillating two‐stream instability (OTSI). Wang et al. (2016) claim that they cannot separate the HF‐enhanced plasma and ion lines excited by O or X mode in the EISCAT UHF radar spectra. Because of this they distinguished the parametric instability excited by O‐/X‐mode heating waves according to their different excitation heights. Their reflection heights were determined from ionosonde records, which provide a rough measure of excitation altitudes and cannot be used for the separation of the O‐ and X‐mode effects. The serious limitation in their analysis is the use of a 30 s integration time of the UHF radar data. There are also serious disagreements between their analysis and the real observational facts. The fact is that it is the radical difference in the behavior of the X‐ and O‐mode plasma and ion line spectra derived with a 5 s resolution, which provides the correct separation of the X‐ and O‐mode effects. It is not discussed and explained how the parallel component of the electric field under X‐mode heating is generated. Apart from the leakage to the O mode, results by Wang et al. (2016) do not explain the potential mechanisms for PDI and OTSI and add nothing to understanding the physical factors accounting for the parametric instability generated by an X‐mode HF pump wave.

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Section: Introductionmentioning

confidence: 99%

Comment on “Parametric Instability Induced by X‐Mode Wave Heating at EISCAT” by Wang et al. (2016)

2017

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“…However, recent experimental data, obtained at the EISCAT (European Incoherent Scatter Scientific Association) HF heating facility, demonstrate that an X ‐polarized HF pump wave can also produce the artificial field‐aligned irregularities (FAI), HF‐enhanced ion, and plasma lines (HFIL and HFPL) in the EISCAT UHF radar spectra. The phenomena mentioned above were generated in the underdense ionosphere in the frequency band f x F 2 ≥ f H > f o F 2 for any heater frequencies in the range f H = 4–8 MHz, where O ‐mode effects cannot be excited at all [ Blagoveshchenskaya et al ., , ]. In addition, only for the higher heater frequencies ( f H > 6 MHz) can the HFIL and HFPL also be excited even in the overdense ionosphere, f H < f o F 2 [ Senior et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Optical and ionospheric phenomena at EISCAT under continuous X‐mode HF pumping

et al. 2014

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We present experimental results from multiinstrument observations in the high-latitude ionospheric F 2 layer at the EISCAT (European Incoherent Scatter Scientific Association) heating facility. The results come from a set of experiments, when an X-polarized HF pump wave at high heater frequencies (f H > 6.0 MHz) was injected into the F region of the ionosphere toward the magnetic zenith. Experiments were carried out under quiet magnetic conditions with an effective radiated power of 458-548 MW. HF pumping was produced at different heater frequencies, away from electron gyroharmonic frequencies, and different durations of heater pulses. We show the first experimental evidence of the excitation of artificial optical emissions at red (630 nm) and green (557.7 nm) lines in the high-latitude ionospheric F 2 layer induced by an X-polarized HF pump wave. Intensities at red and green lines varied in the range 110-950 R and 50-350 R, respectively, with a ratio of green to red line of 0.35-0.5. The results of optical observations are compared with behaviors of the HF-enhanced ion and plasma lines from EISCAT UHF incoherent scatter radar data and small-scale field-aligned artificial irregularities from Cooperative UK Twin Located Auroral Sounding System observations. It was found that the X-mode radio-induced optical emissions coexisted with HF-enhanced ion and plasma lines and strong artificial field-aligned irregularities throughout the whole heater pulse. It is indicative that parametric decay or oscillating two-stream instabilities were not quenched by fully established small-scale field-aligned artificial irregularities excited by an X-mode HF pump wave.

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“…Another experiment was conducted under X-mode pump wave from 16:00 UT to 17:00 UT on 8 March 2010 with 10 min on and 5 min off cycle [Blagoveshchenskaya et al, 2013]. The ERP of heating wave was 123 MW with the frequency of 5.423 MHz.…”

Section: 1002/2016ja022411mentioning

confidence: 99%

A theoretical investigation on the parametric instability excited by X‐mode polarized electromagnetic wave at Tromsø

et al. 2016

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Recent ionospheric modification experiments performed at Tromsø, Norway, have indicated that X‐mode pump wave is capable of stimulating high‐frequency enhanced plasma lines, which manifests the excitation of parametric instability. This paper investigates theoretically how the observation can be explained by the excitation of parametric instability driven by X‐mode pump wave. The threshold of the parametric instability has been calculated for several recent experimental observations at Tromsø, illustrating that our derived equations for the excitation of parametric instability for X‐mode heating can explain the experimental observations. According to our theoretical calculation, a minimum fraction of pump wave electric field needs to be directed along the geomagnetic field direction in order for the parametric instability threshold to be met. A full‐wave finite difference time domain simulation has been performed to demonstrate that a small parallel component of pump wave electric field can be achieved during X‐mode heating in the presence of inhomogeneous plasma.

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Plasma modifications induced by an X-mode HF heater wave in the high latitude F region of the ionosphere

Cited by 28 publications

References 35 publications

Comment on “Parametric Instability Induced by X‐Mode Wave Heating at EISCAT” by Wang et al. (2016)

Comment on “Parametric Instability Induced by X‐Mode Wave Heating at EISCAT” by Wang et al. (2016)

Optical and ionospheric phenomena at EISCAT under continuous X‐mode HF pumping

A theoretical investigation on the parametric instability excited by X‐mode polarized electromagnetic wave at Tromsø

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