scholarly journals Simultaneous observations of quasi-periodic ELF/VLF wave emissions and electron precipitation by DEMETER satellite: A case study

2013 ◽  
Vol 118 (7) ◽  
pp. 4523-4533 ◽  
Author(s):  
M. Hayosh ◽  
D. L. Pasmanik ◽  
A. G. Demekhov ◽  
O. Santolik ◽  
M. Parrot ◽  
...  
Keyword(s):  
Electron Precipitation ◽  
Demeter Satellite

scholarly journals Statistical correlation of spectral broadening in VLF transmitter signal and low-frequency ionospheric turbulence from observation on DEMETER satellite

2008 ◽  
Vol 8 (5) ◽  
pp. 1105-1111 ◽  
Author(s):  
A. Rozhnoi ◽  
M. Solovieva ◽  
O. Molchanov ◽  
O. Akentieva ◽  
J. J. Berthelier ◽  
...  
Keyword(s):  
Middle Latitude ◽  
Statistical Correlation ◽  
Occurrence Rate ◽  
Signal Spectrum ◽  
Ionospheric Turbulence ◽  
Low Latitude ◽  
Demeter Satellite ◽  
Ion Cyclotron ◽  
Latitude Region

Abstract. In our earlier papers we have found the effect of VLF transmitter signal depression over epicenters of the large earthquakes from observation on the French DEMETER satellite that can be considered as new method of global diagnostics of seismic influence on the ionosphere. At present paper we investigate a possibility VLF signal-ionospheric turbulence interaction using additional characteristic of VLF signal-spectrum broadening. This characteristic is important for estimation of the interaction type: linear or nonlinear scattering. Our main results are the following: – There are two zones of increased spectrum broadening, which are centered near magnetic latitudes Φ=±10° and Φ=±40°. Basing on the previous case study research and ground ionosonde registrations, probably it is evidence of nonlinear (active) scattering of VLF signal on the ionospheric turbulence. However occurrence rate of spectrum broadening in the middle-latitude area is higher than in the near-equatorial zone (~15–20% in comparison with ~100% in former area) that is probably coincides with the rate of ionospheric turbulence. – From two years statistics of observation in the selected 3 low-latitude regions and 1 middle-latitude region inside reception area of VLF signal from NWC transmitter we find a correlation of spectrum broadening neither with ion-cyclotron noise (f=150–500 Hz), which possibly means poor representation of the turbulence by the noise due to its mixture with natural ELF emission (which correlates with whistler), nor with magnetic storm activity. – We find rather evident correlation of ion-cyclotron frequency noise, VLF signal depression and weak correlation of spectrum broadening with seismicity in the middle-latitude region over Japan. But in the low-latitude regions we do not find such a correlation. Statistical decrease of VLF signal supports our previous case study results. However rather weak spectrum broadening-seismicity statistical correlation means probably that passive scattering prevails upon nonlinear (active) one.

scholarly journals DEMETER satellite observations of lightning-induced electron precipitation

2007 ◽  
Vol 34 (7) ◽  
Author(s):  
U. S. Inan ◽  
D. Piddyachiy ◽  
W. B. Peter ◽  
J. A. Sauvaud ◽  
M. Parrot
Keyword(s):  
Satellite Observations ◽  
Electron Precipitation ◽  
Demeter Satellite

scholarly journals Modeling of nonstationary electron precipitation by the whistler cyclotron instability

1998 ◽  
Vol 16 (11) ◽  
pp. 1455-1460 ◽  
Author(s):  
A. G. Demekhov ◽  
A. A. Lyubchich ◽  
V. Y. Trakhtengerts ◽  
E. E. Titova ◽  
J. Manninen ◽  
...  
Keyword(s):  
Linear Equations ◽  
Energetic Electron ◽  
Electron Precipitation ◽  
Plasma Parameters ◽  
Wave Interactions ◽  
Cyclotron Maser ◽  
Consistent Model ◽  
Storms And Substorms ◽  
Auroral Phenomena

Abstract. We study a simple self-consistent model of a whistler cyclotron maser derived from the full set of quasi-linear equations. We employ numerical calculations to demonstrate dependencies of pulsation regimes of whistler-mode wave interactions with energetic electrons on plasma parameters. Possible temporal evolution of those regimes in real conditions is discussed; calculations are compared with case-study experimental data on energetic electron precipitation pulsations. A reasonable agreement of the model results and the observations has been found.Key words. Magnetospheric physics (Auroral phenomena; Energetic particles · precipitating; Storms and substorms)

scholarly journals Comparative study on earthquake and ground based transmitter induced radiation belt electron precipitation at middle latitudes

2011 ◽  
Vol 11 (7) ◽  
pp. 1901-1913 ◽  
Author(s):  
N. F. Sidiropoulos ◽  
G. Anagnostopoulos ◽  
V. Rigas
Keyword(s):  
Radiation Belt ◽  
Energetic Electron ◽  
Flux Ratio ◽  
Electron Precipitation ◽  
Total Electron ◽  
Middle Latitudes ◽  
Band Emission ◽  
Electromagnetic Interactions ◽  
Demeter Satellite ◽  
Earthquake Prediction Research

Abstract. We examined (peak-to-background flux ratio p/b > 20) energetic electron bursts in the presence of VLF activity, as observed from the DEMETER satellite at low altitudes (~700 km). Our statistical analysis of measurements during two 6-month periods suggests that: (a) the powerful transmitter NWC causes the strongest effects on the inner radiation belts in comparison with other ground-based VLF transmitters, (b) the NWC transmitter was responsible for only ~1.5 % of total electron bursts examined during the 6-month period (1 July 2008 to 31 December 2008), (c) VLF transmitter-related electron bursts are accompanied by the presence of a narrow band emission centered at the radiating frequency emission, whereas the earthquake-related electron bursts are accompanied by the presence of broadband emissions from a few kHz to >20 KHz, (d) daytime events are less preferable than nighttime events, but this asymmetry was found to be less evident when the powerful transmitter NWC was turned off and (d) seismic activity most probably dominated the electromagnetic interactions producing the electron precipitation at middle latitudes. The results of this study support the proposal that the detection of radiation belt electron precipitation, besides other kinds of studies, is a useful tool for earthquake prediction research.

scholarly journals Burst increases of precipitating electrons recorded by the DEMETER satellite before strong earthquakes

2013 ◽  
Vol 13 (1) ◽  
pp. 197-209 ◽  
Author(s):  
X. Zhang ◽  
C. Fidani ◽  
J. Huang ◽  
X. Shen ◽  
Z. Zeren ◽  
...  
Keyword(s):  
Strong Earthquake ◽  
Invariant Space ◽  
Energy Bands ◽  
Strong Earthquakes ◽  
Electron Counting ◽  
Demeter Satellite ◽  
Electro Magnetic ◽  
Short Time ◽  
Two Peaks

Abstract. This case study developed a method for data processing over six years, from 2004 to 2010, of 70 keV–2.3 MeV electrons recorded by the DEMETER (Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions) satellite. Short time increases in electron counting rates, having 99% probabilities of not being Poisson fluctuations, were statistically selected using geomagnetic invariant space and called electron bursts. Temporal series were analysed confirming the seasonal variations in low energy bands of 70–450 keV. Differently from previous results, the DEMETER results exhibited two peaks of electron bursts: one in the period June–August and one in the period December–February annually. Specifically, six earthquake cases are presented in detail having increases in electron burst number prior to events. Moreover, electron burst precipitation occurring before each strong earthquake of the entire period over the life of the satellite with M ≥ 7.0 was verified as having a probability greater than 97% of not being of a statistical origin. Low energetic electrons in 70–330 keV resulted occurring more frequently near seismic activity than those observed in 330 keV–2.34 MeV energy bands at the satellite altitude in the ionosphere.

scholarly journals A case study of electron precipitation fluxes due to plasmaspheric hiss

2015 ◽  
Vol 120 (8) ◽  
pp. 6736-6748 ◽  
Author(s):  
Rachael Hardman ◽  
Mark A. Clilverd ◽  
Craig J. Rodger ◽  
James B. Brundell ◽  
Roger Duthie ◽  
...  
Keyword(s):  
Electron Precipitation

scholarly journals What can we learn from HF signal scattered from a discrete arc?

2009 ◽  
Vol 27 (5) ◽  
pp. 1887-1896 ◽  
Author(s):  
E. Séran ◽  
M. Godefroy ◽  
K. Kauristie ◽  
J.-C. Cerisier ◽  
J.-J. Berthelier ◽  
...  
Keyword(s):  
Electron Density ◽  
Hf Radar ◽  
Electron Precipitation ◽  
Strong Electron ◽  
Arc Erosion ◽  
Demeter Satellite ◽  
Weak Intensity ◽  
Substorm Activity ◽  
Meso Scale

Abstract. We present observations of a discrete southward propagating arc which appeared in the mid-night sector at latitudes equatorward of main substorm activity. The arc observations were made simultaneously by the ALFA (Auroral Light Fine Analysis) optical camera, the SuperDARN-CUTLASS HF radar and the Demeter satellite during a coordinated multi-instrumental campaign conducted at the KEOPS/ESRANGE site in December 2006. The SuperDARN HF signal which is often lost in the regions of strong electron precipitation yields in our case clear backscatter from an isolated arc of weak intensity. Consequently we are able to study arc dynamics, the formation of meso-scale irregularities of the electron density along the arc, compare the arc motion with the convection of surrounding plasma and discuss the contribution of ionospheric ions in the arc erosion and its propagation.

scholarly journals Electron precipitation from EMIC waves: A case study from 31 May 2013

2015 ◽  
Vol 120 (5) ◽  
pp. 3618-3631 ◽  
Author(s):  
Mark A. Clilverd ◽  
Roger Duthie ◽  
Rachael Hardman ◽  
Aaron T. Hendry ◽  
Craig J. Rodger ◽  
...  
Keyword(s):  
Electron Precipitation ◽  
Emic Waves

The Genesis and Internal Dynamics of El Salvador's People's Revolutionary Army, 1970–1976

2014 ◽  
Vol 38 (01) ◽  
pp. 102-129
Author(s):  
ALBERTO MARTÍN ÁLVAREZ ◽  
EUDALD CORTINA ORERO
Keyword(s):  
Latin America ◽  
El Salvador ◽  
Early Years ◽  
Left Wing ◽  
Internal Dynamics ◽  
Internal Coherence ◽  
The 1960S

AbstractUsing interviews with former militants and previously unpublished documents, this article traces the genesis and internal dynamics of the Ejército Revolucionario del Pueblo (People's Revolutionary Army, ERP) in El Salvador during the early years of its existence (1970–6). This period was marked by the inability of the ERP to maintain internal coherence or any consensus on revolutionary strategy, which led to a series of splits and internal fights over control of the organisation. The evidence marshalled in this case study sheds new light on the origins of the armed Salvadorean Left and thus contributes to a wider understanding of the processes of formation and internal dynamics of armed left-wing groups that emerged from the 1960s onwards in Latin America.

Culture and the plasticity of perception

2020 ◽  
Vol 43 ◽  
Author(s):  
Michael Lifshitz ◽  
T. M. Luhrmann
Keyword(s):  
Cultural Context ◽  
Sensory Experience ◽  
Cultural Learning ◽  
The World

Abstract Culture shapes our basic sensory experience of the world. This is particularly striking in the study of religion and psychosis, where we and others have shown that cultural context determines both the structure and content of hallucination-like events. The cultural shaping of hallucinations may provide a rich case-study for linking cultural learning with emerging prediction-based models of perception.

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