scholarly journals Joint observations of a traveling ionospheric disturbance with the Paratunka OMTI camera and the Hokkaido HF radar

2009 ◽  
Vol 27 (6) ◽  
pp. 2399-2406 ◽  
Author(s):  
A. Koustov ◽  
N. Nishitani ◽  
P. V. Ponomarenko ◽  
K. Shiokawa ◽  
S. Suzuki ◽  
...  
Keyword(s):  
Electric Field ◽  
Ray Tracing ◽  
Plasma Density ◽  
Ionospheric Disturbance ◽  
Depletion Region ◽  
Hf Radar ◽  
Field Of View ◽  
Ionosphere Modeling ◽  
Longitudinal Sector ◽  
Airglow Intensity

Abstract. On 10 September 2007 between 10:00 and 14:00 UT, the OMTI all-sky imager at Paratunka (Kamchatka, Russia, GLAT~52°) observed the onset and south-western progression of a localized depletion region in the airglow intensity. The perturbation, while being stretched in the NW-SE direction, crossed the entire field of view of the camera. During the event, the Hokkaido SuperDARN HF radar was monitoring echoes in the Paratunka longitudinal sector. It was detecting a localized band of ground scatter echoes progressing equatorward synchronously with the motion of the optical perturbation. It is suggested that both features resulted from the onset and south-western progression of a localized region with enhanced electric field that influenced the distribution of the plasma density in the ionosphere. Modeling of the HF ground scatter dynamics based on numerical ray tracing demonstrated qualitative consistency with the observations.

scholarly journals The synthesis of travelling ionospheric disturbance (TID) signatures in HF radar observations using ray tracing

2000 ◽  
Vol 18 (1) ◽  
pp. 56-64 ◽  
Author(s):  
A. J. Stocker ◽  
N. F. Arnold ◽  
T. B. Jones
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Ionospheric Disturbance ◽  
Density Perturbation ◽  
Hf Radar ◽  
Ionospheric Disturbances ◽  
F Region ◽  
Abstract Characteristic ◽  
Electron Density Perturbation ◽  
Radar Frequency

Abstract. Characteristic signatures are often observed in HF radar range-time-intensity plots when travelling ionospheric disturbances (TIDs) are present. These signatures, in particular the variation of the F-region skip distance, have been synthesised using a ray tracing model. The magnitude of the skip variation is found to be a function of the peak electron density perturbation associated with the TID and radar frequency. Examination of experimental observations leads to an estimate of the peak electron density perturbation amplitude of around 25% for those TIDs observed by the CUTLASS radar system. The advantage of using the skip variation over the radar return amplitude as an indicator of density perturbation is also discussed. An example of a dual radar frequency experiment has been given. The investigation of the effect of radar frequency on the observations will aid the optimisation of future experiments..Key words. Ionosphere (auroral ionosphere; ionosphere -atmosphere interactions; ionospheric disturbances)

Influence of inhomogeneities of the plasma density and electric field on the generation of electrostatic noise in the auroral zone

2015 ◽  
Vol 41 (3) ◽  
pp. 254-261 ◽  
Author(s):  
A. A. Chernyshov ◽  
A. A. Ilyasov ◽  
M. M. Mogilevskii ◽  
I. V. Golovchanskaya ◽  
B. V. Kozelov
Keyword(s):  
Electric Field ◽  
Plasma Density ◽  
Auroral Zone

Ray Tracing Synthesis of HF Radar Signatures from Gaussian Plasma Clouds

1971 ◽  
Author(s):  
Pendyala B. Rao ◽  
E. M. Allen ◽  
George D. Thome
Keyword(s):  
Ray Tracing ◽  
Hf Radar ◽  
Radar Signatures

scholarly journals Mid-latitude ionospheric scintillation anomaly in the Far East

2003 ◽  
Vol 21 (2) ◽  
pp. 577-581 ◽  
Author(s):  
L. A. Hajkowicz ◽  
H. Minakoshi
Keyword(s):  
Comprehensive Evaluation ◽  
Ionospheric Disturbance ◽  
Far East ◽  
Ionospheric Scintillation ◽  
F Region ◽  
Longitudinal Sector ◽  
E Region ◽  
Latitude Region ◽  
One Year

Abstract. A long-term (over 3 years) study has been undertaken to obtain a comprehensive evaluation of VHF ionospheric scintillation morphology in East Asia (at Kokobunji in Japan), using amplitude records from Transit satellites. It is now evident that summer day and night scintillation enhancement in this mid-latitude region is a long-term evidence of a well-known Asian ionospheric disturbance anomaly. The scintillation activity is particularly strong during summer nights (21:00–24:00 LT) and on occasion, all satellite passes recorded on consecutive days are associated with pronounced scintillation activity. A second sub-maximum is observed in the summer pre-noon period (09:00–12:00 LT). The scintillation regions extend latitudinally for a distance of 400–600 km in the F-region and 100–200 km in the E-region, mostly equatorwards of Kokobunji. For comparison similar scintillation data obtained for one year at the same longitudinal sector but in southern mid-latitudes (Brisbane in Australia) were compared with the simultaneous northern scintillation data. The scintillation activity at Brisbane was much less pronounced in the southern summer but was of the same low level during other seasons as that for Kokobunji. This consistent scintillation anomaly, as yet, has not been included in the global scintillation models, which are essential for radio-satellite communications.Key words. Ionosphere (mid-latitude ionosphere; ionospheric irregularities)

scholarly journals Simultaneous optical, CUTLASS HF radar, and FAST spacecraft observations: signatures of boundary layer processes in the cusp

2004 ◽  
Vol 22 (2) ◽  
pp. 511-525 ◽  
Author(s):  
K. Oksavik ◽  
F. Søraas ◽  
J. Moen ◽  
R. Pfaff ◽  
J. A. Davies ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Broad Band ◽  
Spectral Width ◽  
Hf Radar ◽  
Optical Data ◽  
Low Energy Electrons ◽  
Field Lines ◽  
Auroral Phenomena ◽  
Electric Fields And Currents

Abstract. In this paper we discuss counterstreaming electrons, electric field turbulence, HF radar spectral width enhancements, and field-aligned currents in the southward IMF cusp region. Electric field and particle observations from the FAST spacecraft are compared with CUTLASS Finland spectral width enhancements and ground-based optical data from Svalbard during a meridional crossing of the cusp. The observed 630nm rayed arc (Type-1 cusp aurora) is associated with stepped cusp ion signatures. Simultaneous counterstreaming low-energy electrons on open magnetic field lines lead us to propose that such electrons may be an important source for rayed red arcs through pitch angle scattering in collisions with the upper atmosphere. The observed particle precipitation and electric field turbulence are found to be nearly collocated with the equatorward edge of the optical cusp, in a region where CUTLASS Finland also observed enhanced spectral width. The electric field turbulence is observed to extend far poleward of the optical cusp. The broad-band electric field turbulence corresponds to spatial scale lengths down to 5m. Therefore, we suggest that electric field irregularities are directly responsible for the formation of HF radar backscatter targets and may also explain the observed wide spectra. FAST also encountered two narrow highly structured field-aligned current pairs flowing near the edges of cusp ion steps. Key words. Ionosphere (electric fields and currents). Magnetosphere physics (magnetopause, cusp, and boundary layers; auroral phenomena)

scholarly journals Heights of SuperDARN F region echoes estimated from the analysis of HF radio wave propagation

2007 ◽  
Vol 25 (9) ◽  
pp. 1987-1994 ◽  
Author(s):  
A. V. Koustov ◽  
D. André ◽  
E. Turunen ◽  
T. Raito ◽  
S. E. Milan
Keyword(s):  
Electron Density ◽  
Hf Radar ◽  
Field Of View ◽  
Data Set ◽  
Density Distributions ◽  
F Region ◽  
The Earth ◽  
Earth Magnetic Field ◽  
Field Lines ◽  
Radar Wave

Abstract. Tomographic estimates of the electron density altitudinal and latitudinal distribution within the Hankasalmi HF radar field of view are used to predict the expected heights of F region coherent echoes by ray tracing and finding ranges of radar wave orthogonality with the Earth magnetic field lines. The predicted ranges of echoes are compared with radar observations concurrent with the tomographic measurements. Only those events are considered for which the electron density distributions were smooth, the band of F region HF echoes existed at ranges 700–1500 km, and there was a reasonable match between the expected and measured slant ranges of echoes. For a data set comprising of 82 events, the typical height of echoes was found to be 275 km.

Inhomogeneities of plasma density and electric field as sources of electrostatic turbulence in the auroral region

2015 ◽  
Vol 22 (3) ◽  
pp. 032906 ◽  
Author(s):  
Askar A. Ilyasov ◽  
Alexander A. Chernyshov ◽  
Mikhail M. Mogilevsky ◽  
Irina V. Golovchanskaya ◽  
Boris V. Kozelov
Keyword(s):  
Electric Field ◽  
Plasma Density ◽  
Auroral Region

Design of Metal-Semiconductor-Metal Ultra-Violet Detector on Gallium Nitride

2001 ◽  
Vol 680 ◽  
Author(s):  
Wenhua Gu ◽  
Soo Jin Chua ◽  
Xin Hai Zhang
Keyword(s):  
Gallium Nitride ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Ultra Violet ◽  
Depletion Region ◽  
Structure Parameters ◽  
Metal Semiconductor Metal ◽  
Effective Electric Field ◽  
Response Current

ABSTRACTThe design of Gallium Nitride based Metal-Semiconductor-Metal Ultra-Violet detector is discussed. We introduce a simulation model using Medici to describe the performances of such detectors. Structure parameters, such as the inter-digitated electrode dimension and the GaN layer thickness, are optimized for response current and time using this model. The simulation results can be explained by the variation of depletion region. We introduce the “effective electric field intensity” to describe the depletion region. The relationship between the “effective electric field intensity” and structure parameters are simulated and discussed.

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