Study of the lower hybrid resonance frequency over the regions of gathering earthquakes using DEMETER data

Vavilov, Dmitrii; Shklyar, D. R.; Титова, Е. Е.; Parrot, M.

doi:10.1016/j.jastp.2013.03.019

Cited by 12 publications

(14 citation statements)

References 39 publications

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“…It has been proposed by Vavilov et al. (2013) and Zhang et al. (2017) that this phenomenon is due to the magnetospheric reflection above DEMETER orbit (660 km) for nonducted waves, where the local LHR frequency is higher than F 1 frequency.…”

Section: Methodsmentioning

confidence: 95%

Alpha Transmitter Signal Reflection and Triggered Emissions

Chen

Xia

et al. 2020

Geophysical Research Letters

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Russian Alpha radio navigation system (RSDN-20) emits F 1 = 11.9 kHz signals into the magnetosphere which propagate as whistler mode waves. Observed by waveform continuous burst mode from Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) on Van Allen Probes, a case is presented and featured with ducted propagation, multiple reflections, and triggered emissions. Both risers and fallers appear in the triggered emissions. We use a ray tracing method to demonstrate ducted propagation, which has a similar wave normal angle near 150°as the observation. The arrival time of reflected signals is estimated using propagation analysis and compared with the observed signal arrival time. To test the nonlinear cyclotron resonance theory, the interaction region scale and the order of chirping rate in triggered emission are estimated. The estimated interaction region scale of MLAT = −3°is smaller than the observed MLAT = −6°. The discrepancy may be caused by the parallel propagation assumption and background field model.

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Section: Methodsmentioning

confidence: 95%

Alpha Transmitter Signal Reflection and Triggered Emissions

Chen

Xia

et al. 2020

Geophysical Research Letters

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“…The small geomagnetic field intensity at the conjugate Southern Hemisphere of KRA means small electron cyclotron frequency here, and the collision frequency profile will play the major role in VLF wave propagation, so it may cause the further attenuation of VLF waves. Taking account of the LHR at the conjugate area, the signals would be reflected magnetospherically from the region where f = f LHR [Vavilov et al, 2013], and they could not be observed at the lower ionosphere with high f LHR , so the almost disappeared signals at the Southern Hemisphere might also contribute to its f LHR over the KRA conjugate area.…”

Section: Discussionmentioning

confidence: 99%

“…The second reason is considered from the effects of the lower hybrid resonance (LHR) frequency in the ionosphere. Vavilov et al [] had calculated the LHR frequency at satellite altitude by using the Demeter observing data from Langmuir Probe and Ion Analyzer for plasma densities. Their results revealed that over the west station KRA, the maximal LHR frequency reached about 13.2 kHz in winter night at 660 km altitude, which would enlarge the refractive index and strongly affect the penetration of VLF waves lower than this frequency into the ionosphere.…”

Section: Discussionmentioning

confidence: 99%

The spatial distribution features of three Alpha transmitter signals at the topside ionosphere

et al. 2017

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The spatial distribution features of electric field over three Alpha transmitters in Russia were analyzed based on the Demeter satellite records at local nighttime during the solar minimum in December of 2008, where the three transmitters are with the same emitted power of 500 kW and the same radio waves at 11.9 kHz, 12.6 kHz, and 14.9 kHz. The results of observations showed that the maximal electric field reached −80 to −70 dB (hereafter referred as to V/m) at 660 km altitude, and the horizontal covered area even exceeded 80° in longitude with electric field above −100 dB at 14.9 kHz. The lowest electric field and the smallest longitude scale were detected over Krasnodar (KRA), which is demonstrated that the lower ionosphere plays an important role in attenuating the energy as suggested by the simulation results from the full‐wave propagation model. Another feature over KRA was the significant decrease in electromagnetic field strength at 11.9 kHz and 12.6 kHz, being one order of magnitude lower than the other two transmitters, where the lower hybrid resonance waves affected severely the whistler mode wave mode propagation. Compared with the ground very low frequency observations at Tonghai and Ya'an in China, the most complex variations were observed from KRA, while the east transmitter Khabarovsk maintained high strength of electromagnetic power in a longer distance than the middle transmitter Novosibirsk in local nighttime, which is consistent with the large covering scale in the topside ionosphere due to the enhancement by wave‐particle interaction from the other transmitter.

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“…Transient changes in composition can occur hundreds of miles from the source of a disturbance. Previous satellites such as DEMETER and C/NOFS has employed in situ electric field instruments to record the spectrum plasma waves from lightning, earthquake precursors and CME driven storms (Holzworth et al., 2011; Parrot, Berthelier, et al., 2008; Vavilov et al., 2013, Zhima et al., 2014). Some plasma wave emissions have elusive origins.…”

Section: Introductionmentioning

confidence: 99%

Satellite Observations of Strong Plasma Wave Emissions With Frequency Shifts Induced by an Engine Burn From the Cygnus Spacecraft

et al. 2021

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A new discovery was made using the radio receiver instrument on the Canadian enhanced polar outflow probe (e‐POP) showing that strong plasma wave emissions (SPWE) are seen near 17 kHz and 300 Hz. The frequency of these emissions are affected by small injections of neutral gas from the Cygnus spacecraft. The technique of using a 150 g/s thruster to change frequencies and intensities of plasma waves has provided evidence that a finite kz lower hybrid mode may the source of the SPWE waves. SPWE observations in space are a sensitive diagnostic tool to measure both natural and manmade changes in the earth's ion composition.

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Study of the lower hybrid resonance frequency over the regions of gathering earthquakes using DEMETER data

Cited by 12 publications

References 39 publications

Alpha Transmitter Signal Reflection and Triggered Emissions

Alpha Transmitter Signal Reflection and Triggered Emissions

The spatial distribution features of three Alpha transmitter signals at the topside ionosphere

Satellite Observations of Strong Plasma Wave Emissions With Frequency Shifts Induced by an Engine Burn From the Cygnus Spacecraft

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