VHF and HF radar measurements of E and F region plasma drifts at the magnetic equator

1992 ◽  
Vol 97 (A3) ◽  
pp. 3011-3017 ◽  
Author(s):  
K. S. Viswanathan ◽  
S. P. Namboothiri ◽  
P. B. Rao
Keyword(s):  
Magnetic Equator ◽  
Hf Radar ◽  
F Region ◽  
Plasma Drifts ◽  
Radar Measurements ◽  
Region Plasma

Vertical plasma drifts in the F region at the magnetic equator

1989 ◽  
Vol 94 (A9) ◽  
pp. 12055 ◽  
Author(s):  
S. P. Namboothiri ◽  
N. Balan ◽  
P. B. Rao
Keyword(s):  
Magnetic Equator ◽  
F Region ◽  
Plasma Drifts

scholarly journals Multi-frequency HF radar measurements of artificial F-region field-aligned irregularities

2004 ◽  
Vol 22 (10) ◽  
pp. 3503-3511 ◽  
Author(s):  
A. Senior ◽  
N. D. Borisov ◽  
M. J. Kosch ◽  
T. K. Yeoman ◽  
F. Honary ◽  
...  
Keyword(s):  
Wave Interaction ◽  
Operating Mode ◽  
Hf Radar ◽  
Heating Facility ◽  
F Region ◽  
Density Perturbations ◽  
Radar Measurements ◽  
The Mean ◽  
Power Measurements ◽  
Field Aligned Irregularities

Abstract. We present radar backscatter power measurements using the CUTLASS HF radar at Hankasalmi, Finland from F-region field-aligned irregularities induced by HF radio pumping with the EISCAT Heating facility. A novel radar operating mode is used in which the radar frequency is rapidly swept through a number of bands, making use of the varying ionospheric refraction to probe different heights within the heated region. We obtain height profiles of backscatter power which correspond to e-folding scale lengths of around 20km for the mean-square electron density perturbations for pump wave interaction heights in the region of 240-250km in daytime conditions. The results are in agreement with previous measurements made by other techniques. We discuss some problems with the method and suggest improvements for future experiments.

Vertical plasma drifts in the post-sunset F-region at the magnetic equator

1988 ◽  
Vol 50 (12) ◽  
pp. 1087-1091 ◽  
Author(s):  
S.P. Namboothiri ◽  
B. Jayachandran ◽  
N. Balan ◽  
P.B. Rao
Keyword(s):  
Magnetic Equator ◽  
F Region ◽  
Plasma Drifts

scholarly journals Equatorial 150 km echoes and daytime F region vertical plasma drifts in the Brazilian longitude sector

2013 ◽  
Vol 31 (10) ◽  
pp. 1867-1876 ◽  
Author(s):  
F. S. Rodrigues ◽  
E. B. Shume ◽  
E. R. de Paula ◽  
M. Milla
Keyword(s):  
Time Variation ◽  
Doppler Velocity ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Radio Observatory ◽  
F Region ◽  
Plasma Drifts ◽  
Radar Measurements ◽  
Coherent Backscatter ◽  
Ionospheric Drifts

Abstract. Previous studies showed that conventional coherent backscatter radar measurements of the Doppler velocity of the so-called 150 km echoes can provide an alternative way of estimating ionospheric vertical plasma drifts during daytime hours (Kudeki and Fawcett, 1993; Chau and Woodman, 2004). Using observations made by a small, low-power 30 MHz coherent backscatter radar located in the equatorial site of São Luís (2.59° S, 44.21° W; −2.35° dip lat), we were able to detect and monitor the occurrence of 150 km echoes in the Brazilian sector. Using these measurements we estimated the local time variation of daytime vertical ionospheric drifts in the eastern American sector. Here, we present a few interesting cases of 150 km-echoes observations made by the São Luís radar and estimates of the diurnal variation of vertical drifts. These cases exemplify the variability of the vertical drifts in the Brazilian sector. Using same-day 150 km-echoes measurements made at the Jicamarca Radio Observatory in Peru, we also demonstrate the variability of the equatorial vertical drifts across the American sector. In addition to first estimates of the absolute vertical plasma drifts in the eastern American (Brazilian) sector, we also present observations of abnormal drifts detected by the São Luís radar associated with the 2009 major sudden stratospheric warming event.

scholarly journals On the relationship between the velocity of E-region HF echoes and <i>E</i>x<i>B</i> plasma drift

2005 ◽  
Vol 23 (2) ◽  
pp. 371-378 ◽  
Author(s):  
A. V. Koustov ◽  
D. W. Danskin ◽  
R. A. Makarevitch ◽  
J. D. Gorin
Keyword(s):  
Phase Velocity ◽  
Hf Radar ◽  
Line Of Sight ◽  
Plasma Drift ◽  
F Region ◽  
Plasma Drifts ◽  
E Region ◽  
Cross Track ◽  
The Relationship ◽  
Large Flow

Abstract. In this study, velocities of E-region HF echoes observed by the Stokkseyri HF radar are compared with ExB plasma drifts in the F-region measured by the DMSP satellites. Events were selected for which the DMSP track projected to the height of 110km was almost perpendicular to the central beams of the radar, resulting in a direct comparison of the cross-track component of the ExB drift and the line-of-sight HF velocity. We found that the typical ratio of HF velocity to the DMSP drift is ~0.35 in a range of DMSP drifts of 0-1700m/s. It is suggested that E-region HF velocities, observed both along the electrojet and at large flow angles, are significantly affected by scatter from the bottom of the electrojet layer where the irregularity phase velocity is expected to be strongly depressed with respect to the ExB flow.

scholarly journals Signatures of moving polar cap arcs in the F-region PolarDARN echoes

2012 ◽  
Vol 30 (3) ◽  
pp. 441-455 ◽  
Author(s):  
A. V. Koustov ◽  
K. Hosokawa ◽  
N. Nishitani ◽  
K. Shiokawa ◽  
H. Liu
Keyword(s):  
Spectral Width ◽  
Global Scale ◽  
Auroral Oval ◽  
Polar Cap ◽  
Common Features ◽  
F Region ◽  
Radar Network ◽  
Radar Measurements ◽  
Resolute Bay ◽  
Region Plasma

Abstract. Joint observations of the all-sky camera at Resolute Bay (Nunavut, Canada) and the Polar Dual Auroral Radar Network (PolarDARN) HF radars at Rankin Inlet and Inuvik (Canada) are considered to establish radar signatures of poleward moving polar cap arcs "detaching" from the auroral oval. Common features of the events considered are enhanced power or echo occurrence in the wake of the arcs and enhanced spectral width of these echoes. When the arcs were oriented along some of the radar beams, velocity reversals at the arc location were observed with the directions of the arc-associated flows corresponding to a converging electric field. For the event of 9 December 2007, two arcs were poleward progressing almost along the central beams of the Inuvik radar at the speed close to the E × B drift of the bulk of the F-region plasma as inferred from HF Doppler velocities and from independent measurements by the Resolute Bay ionosonde. In global-scale convection maps inferred from all Super Dual Auroral Radar Network (SuperDARN) radar measurements, the polar cap arcs were often seen close to the reversal line of additional mesoscale convection cells located poleward of the normal cells related to the auroral oval.

HF Doppler observations of vector plasma drifts in the evening F-region at the magnetic equator

1992 ◽  
Vol 54 (11-12) ◽  
pp. 1545-1554 ◽  
Author(s):  
N. Balan ◽  
B. Jayachandran ◽  
R. Balachandran Nair ◽  
S.P. Namboothiri ◽  
G.J. Bailey ◽  
...  
Keyword(s):  
Magnetic Equator ◽  
F Region ◽  
Plasma Drifts
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