Evidence of kilometer-scale waves in the lower E region from high resolution VHF radar observations over Gadanki

2002 ◽  
Vol 29 (10) ◽  
pp. 137-1-137-4 ◽  
Author(s):  
A. K. Patra ◽  
S. Sripathi ◽  
V. Siva Kumar ◽  
P. B. Rao
Keyword(s):  
High Resolution ◽  
Vhf Radar ◽  
Radar Observations ◽  
E Region

First VHF radar observations of tropical latitude E-region field aligned irregularities

1996 ◽  
Vol 23 (25) ◽  
pp. 3683-3686 ◽  
Author(s):  
R. K. Choudhary ◽  
K. K. Mahajan ◽  
Sachchidanand Singh ◽  
Keshav Kumar ◽  
V. K. Anandan
Keyword(s):  
Vhf Radar ◽  
Radar Observations ◽  
Tropical Latitude ◽  
E Region ◽  
Field Aligned Irregularities

High-resolution VHF radar observations of turbulence structures in the mesosphere

1979 ◽  
Vol 6 (7) ◽  
pp. 617-620 ◽  
Author(s):  
J. Röttger ◽  
P. K. Rastogi ◽  
R. F. Woodman
Keyword(s):  
High Resolution ◽  
Vhf Radar ◽  
Radar Observations ◽  
Turbulence Structures

Eiscat vhf radar observations of periodic mesopause echoes

1988 ◽  
Vol 36 (4) ◽  
pp. 423-428 ◽  
Author(s):  
H Rishbeth ◽  
AP van Eyken ◽  
B S Lanchester ◽  
T Turunen ◽  
J Röttger ◽  
...  
Keyword(s):  
Vhf Radar ◽  
Radar Observations

scholarly journals Enhanced incoherent scatter plasma lines

1996 ◽  
Vol 14 (12) ◽  
pp. 1462-1472 ◽  
Author(s):  
H. Nilsson ◽  
S. Kirkwood ◽  
J. Lilensten ◽  
M. Galand
Keyword(s):  
High Plasma ◽  
Collision Term ◽  
Vhf Radar ◽  
Detailed Model ◽  
Model Calculations ◽  
Incoherent Scatter ◽  
Incoherent Scatter Radars ◽  
Plasma Line ◽  
E Region ◽  
Radar Measurements

Abstract. Detailed model calculations of auroral secondary and photoelectron distributions for varying conditions have been used to calculate the theoretical enhancement of incoherent scatter plasma lines. These calculations are compared with EISCAT UHF radar measurements of enhanced plasma lines from both the E and F regions, and published EISCAT VHF radar measurements. The agreement between the calculated and observed plasma line enhancements is good. The enhancement from the superthermal distribution can explain even the very strong enhancements observed in the auroral E region during aurora, as previously shown by Kirkwood et al. The model calculations are used to predict the range of conditions when enhanced plasma lines will be seen with the existing high-latitude incoherent scatter radars, including the new EISCAT Svalbard radar. It is found that the detailed structure, i.e. the gradients in the suprathermal distribution, are most important for the plasma line enhancement. The level of superthermal flux affects the enhancement only in the region of low phase energy where the number of thermal electrons is comparable to the number of suprathermal electrons and in the region of high phase energy where the suprathermal fluxes fall to such low levels that their effect becomes small compared to the collision term. To facilitate the use of the predictions for the different radars, the expected signal- to-noise ratios (SNRs) for typical plasma line enhancements have been calculated. It is found that the high-frequency radars (Søndre Strømfjord, EISCAT UHF) should observe the highest SNR, but only for rather high plasma frequencies. The VHF radars (EISCAT VHF and Svalbard) will detect enhanced plasma lines over a wider range of frequencies, but with lower SNR.

scholarly journals A numerical model of the ionosphere, including the E-region above EISCAT

1996 ◽  
Vol 14 (2) ◽  
pp. 191-200 ◽  
Author(s):  
P.-Y. Diloy ◽  
A. Robineau ◽  
J. Lilensten ◽  
P.-L. Blelly ◽  
J. Fontanari
Keyword(s):  
Electric Field ◽  
Fluid Model ◽  
Molecular Ions ◽  
Ion Concentration ◽  
Topside Ionosphere ◽  
Ion Chemistry ◽  
Vhf Radar ◽  
Theoretical Predictions ◽  
Consistent Manner ◽  
E Region

Abstract. It has been previously demonstrated that a two-ion (O+ and H+) 8-moment time-dependent fluid model was able to reproduce correctly the ionospheric structure in the altitude range probed by the EISCAT-VHF radar. In the present study, the model is extended down to the E-region where molecular ion chemistry (NO+ and O+2, essentially) prevails over transport; EISCAT-UHF observations confirmed previous theoretical predictions that during events of intense E×B induced convection drifts, molecular ions (mainly NO+) predominate over O+ ions up to altitudes of 300 km. In addition to this extension of the model down to the E-region, the ionization and heating resulting from both solar insolation and particle precipitation is now taken into account in a consistent manner through a complete kinetic transport code. The effects of E×B induced convection drifts on the E- and F-region are presented: the balance between O+ and NO+ ions is drastically affected; the electric field acts to deplete the O+ ion concentration. The [NO+]/[O+] transition altitude varies from 190 km to 320 km as the perpendicular electric field increases from 0 to 100 mV m-1. An interesting additional by-product of the model is that it also predicts the presence of a noticeable fraction of N+ ions in the topside ionosphere in good agreement with Retarding Ion Mass Spectrometer measurements onboard Dynamic Explorer.

Evidence for specular reflection from monostatic VHF radar observations of the stratosphere

Radio Science ◽  
1978 ◽  
Vol 13 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
K. S. Gage ◽  
J. L. Green
Keyword(s):  
Specular Reflection ◽  
Vhf Radar ◽  
Radar Observations

Spatial domain interferometric VHF radar observations of spread meteor echoes

2002 ◽  
Vol 64 (3) ◽  
pp. 339-347 ◽  
Author(s):  
C Raghava Reddi ◽  
T.V.C Sarma ◽  
P.B Rao
Keyword(s):  
Spatial Domain ◽  
Vhf Radar ◽  
Radar Observations
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