scholarly journals Comparison of the orientation of small-scale electron density irregularities and F region plasma flow direction

2000 ◽  
Vol 18 (8) ◽  
pp. 918-926 ◽  
Author(s):  
E. D. Tereshchenko ◽  
B. Z. Khudukon ◽  
M. O. Kozlova ◽  
O. V. Evstafiev ◽  
T. Nygrén ◽  
...  
Keyword(s):  
Plasma Flow ◽  
Flow Direction ◽  
Small Scale ◽  
Incoherent Scatter ◽  
F Region ◽  
Anisotropy Parameters ◽  
Electron Density Irregularities ◽  
Region Plasma ◽  
Good Agreement ◽  
Field Aligned Irregularities

Abstract. Results are shown from an experimental campaign where satellite scintillation was observed at three sites at high latitudes and, simultaneously, the F region plasma flow was measured by the nearby EISCAT incoherent scatter radar. The anisotropy parameters of field-aligned irregularities are determined from amplitude scintillation using a method based on the variance of the relative logarithmic amplitude. The orientation of the anisotropy in a plane perpendicular to the geomagnetic field is compared with the direction of F region plasma flow. The results indicate that in most cases a good agreement between the two directions is obtained.Key words: Ionosphere (auroral ionosphere; ionospheric irregularities)

scholarly journals Irregular structures of the F layer at high latitudes during ionospheric heating

2000 ◽  
Vol 18 (9) ◽  
pp. 1197-1209 ◽  
Author(s):  
E. D. Tereshchenko ◽  
M. O. Kozlova ◽  
O. V. Evstafiev ◽  
B. Z. Khudukon ◽  
T. Nygrén ◽  
...  
Keyword(s):  
Small Scale ◽  
Auroral Ionosphere ◽  
Perpendicular Anisotropy ◽  
Ionospheric Heating ◽  
Incoherent Scatter ◽  
Active Experiments ◽  
F Region ◽  
Irregular Structures ◽  
Heating Region ◽  
Region Plasma

Abstract. Results on heating the ionospheric F region above Tromsø, Norway are presented. The ionosphere was monitored by satellite tomography and amplitude scintillation methods as well as the EISCAT incoherent scatter radar. No effect of heating was observed in the daytime. In the evening and in the pre-midnight sector, noticeable tilts of the F region were observed during heating periods. The tilts overlapped the heating cone, where the electron density decreased and irregularities exceeding 10 km in size appeared. Between the heating periods the F layer was restored to its horizontal shape. The anisotropic parameters of small-scale irregularities with scale lengths of hundreds of metres were also determined. It was found that the perpendicular anisotropy points in the direction of F region plasma flow. In some cases the results can be explained by assuming that the small-scale irregularities were generated within the heating cone and drifted out of the heating region where they were subsequently observed.Key words: Ionosphere (active experiments; auroral ionosphere; ionospheric irregularities)

scholarly journals Electron heating by HF pumping of high-latitude ionospheric F-region plasma near magnetic zenith

2020 ◽  
Vol 38 (2) ◽  
pp. 297-307 ◽  
Author(s):  
Thomas B. Leyser ◽  
Björn Gustavsson ◽  
Theresa Rexer ◽  
Michael T. Rietveld
Keyword(s):  
Electron Temperature ◽  
Pump Beam ◽  
Electron Heating ◽  
Incoherent Scatter ◽  
F Region ◽  
Left Handed ◽  
Parameter Values ◽  
Uhf Radar ◽  
Region Plasma ◽  
Magnetic Zenith

Abstract. High-frequency electromagnetic pumping of ionospheric F-region plasma at high and mid latitudes gives the strongest plasma response in magnetic zenith, antiparallel to the geomagnetic field in the Northern Hemisphere. This has been observed in optical emissions from the pumped plasma turbulence, electron temperature enhancements, filamentary magnetic field-aligned plasma density irregularities, and in self-focusing of the pump beam in magnetic zenith. We present results of EISCAT (European Incoherent SCATter association) Heating-induced magnetic-zenith effects observed with the EISCAT UHF incoherent scatter radar. With heating transmitting a left-handed circularly polarized pump beam towards magnetic zenith, the UHF radar was scanned in elevation in steps of 1.0 and 1.5∘ around magnetic zenith. The electron energy equation was integrated to model the electron temperature and associated electron heating rate and optimized to fit the plasma parameter values measured with the radar. The experimental and modelling results are consistent with pump wave propagation in the L mode in magnetic zenith, rather than in the O mode.

scholarly journals Predicted and observed characteristics of small-scale field-aligned irregularities generated in the F-region by low power HF heating

2002 ◽  
Vol 20 (5) ◽  
pp. 647-653 ◽  
Author(s):  
E. Kolesnikova ◽  
T. R. Robinson ◽  
J. A. Davies
Keyword(s):  
Low Power ◽  
Decay Rate ◽  
Parametric Instability ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Thermal Parametric Instability ◽  
Hf Heating ◽  
Heated Volume ◽  
Field Aligned Irregularities

Abstract. Simultaneous HF scattering from the different regions of the heated volume is used to investigate characteristics of the small-scale field-aligned irregularities in the F-region. Time of growth, decay rate and saturation level for different pump powers are deduced from the observations and are compared with their behaviour predicted by the thermal parametric instability model. As a result, the estimates of the density and of the temperature modifications inside of the irregularities are obtained.Key words. Ionosphere (ionospheric irregularities)

Analysis of incoherent scatter radar data from non-thermal F-region plasma

1989 ◽  
Vol 51 (6) ◽  
pp. 483-495 ◽  
Author(s):  
K. Suvanto ◽  
M. Lockwood ◽  
K.J. Winser ◽  
A.D. Farmer ◽  
B.J.I. Bromage
Keyword(s):  
Radar Data ◽  
Incoherent Scatter Radar ◽  
Incoherent Scatter ◽  
F Region ◽  
Scatter Radar ◽  
Region Plasma

Artificial Small-scale Field-aligned Irregularities in the High Latitude Ionospheric F-region

2018 ◽  
Author(s):  
Nataly Blagoveshchenskaya ◽  
Tatiana Borisova ◽  
Alexey Kalishin ◽  
Timothy Yeoman
Keyword(s):  
High Latitude ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Field Aligned Irregularities

Artificial small-scale field-aligned irregularities in the high latitude F region of the ionosphere induced by an X-mode HF heater wave

2011 ◽  
Vol 38 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. F. Blagoveshchenskaya ◽  
T. D. Borisova ◽  
T. K. Yeoman ◽  
M. T. Rietveld ◽  
I. M. Ivanova ◽  
...  
Keyword(s):  
High Latitude ◽  
Small Scale ◽  
F Region ◽  
Scale Field ◽  
Field Aligned Irregularities

scholarly journals Tracking F-region plasma depletion bands using GPS-TEC, incoherent scatter radar, and all-sky imaging at Arecibo

2008 ◽  
Vol 60 (6) ◽  
pp. 633-646 ◽  
Author(s):  
Ilgin Seker ◽  
Dorey J. Livneh ◽  
Jonathan J. Makela ◽  
John D. Mathews
Keyword(s):  
Incoherent Scatter Radar ◽  
Gps Tec ◽  
Incoherent Scatter ◽  
F Region ◽  
Scatter Radar ◽  
Plasma Depletion ◽  
Region Plasma

scholarly journals VHF scintillations, orientation of the anisotropy of F-region irregularities and direction of plasma convection in the polar cap

2008 ◽  
Vol 26 (7) ◽  
pp. 1725-1730 ◽  
Author(s):  
E. D. Tereshchenko ◽  
N. Yu. Romanova ◽  
A. V. Koustov
Keyword(s):  
Magnetic Field ◽  
Plasma Flow ◽  
Flow Direction ◽  
Ionospheric Irregularities ◽  
Plasma Convection ◽  
Polar Cap ◽  
Data Set ◽  
Multiple Peaks ◽  
F Region ◽  
The Magnetic Field

Abstract. Scintillation data recorded at the polar cap station Barentsburg are shown to occasionally exhibit two or more peaks in the latitudinal profiles of the amplitude dispersion. Comparison with concurrent SuperDARN radar convection maps indicates that multiple peaks occur when Barentsburg is located within the area of strong changes in the plasma flow direction. When parameters of the ionospheric irregularities are inferred from the scintillation data, the orientation of the irregularity anisotropy in a plane perpendicular to the magnetic field is found to coincide well with the E×B flow direction, individually for each peak of the scintillation data. The differences were found to be mostly less than 20° for a data set comprised of 104 events. The conclusion is made that analysis of scintillation data allows one to infer the direction of plasma flow with a certain degree of detail.

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