Density and electric field fluctuations associated with the gradient drift instability in the high-latitude ionosphere

2004 ◽  
Vol 31 (11) ◽  
pp. n/a-n/a ◽  
Author(s):  
N. A. Gondarenko ◽  
P. N. Guzdar
Keyword(s):  
Electric Field ◽  
High Latitude ◽  
High Latitude Ionosphere ◽  
Field Fluctuations ◽  
Gradient Drift ◽  
Drift Instability

Effects of field line mapping on the gradient-drift instability in the coupled E and F region high-latitude ionosphere

Radio Science ◽  
1994 ◽  
Vol 29 (1) ◽  
pp. 317-335 ◽  
Author(s):  
P. K. Chaturvedi ◽  
M. J. Keskinen ◽  
S. L. Ossakow ◽  
J. A. Fedder
Keyword(s):  
Field Line ◽  
High Latitude ◽  
F Region ◽  
High Latitude Ionosphere ◽  
Gradient Drift ◽  
Drift Instability

Three-dimensional nonlinear simulations of the gradient drift instability in the high-latitude ionosphere

Radio Science ◽  
1998 ◽  
Vol 33 (6) ◽  
pp. 1901-1913 ◽  
Author(s):  
P. N. Guzdar ◽  
N. A. Gondarenko ◽  
P. K. Chaturvedi ◽  
S. Basu
Keyword(s):  
High Latitude ◽  
Three Dimensional ◽  
Nonlinear Simulations ◽  
High Latitude Ionosphere ◽  
Gradient Drift ◽  
Drift Instability

The influence of convection on the structure of the high-latitude ionosphere

1989 ◽  
Vol 328 (1598) ◽  
pp. 119-137 ◽  
Keyword(s):  
Electric Field ◽  
High Latitude ◽  
Numerical Models ◽  
Past History ◽  
Incoherent Scatter ◽  
Convection Electric Field ◽  
Ion Drifts ◽  
High Latitude Ionosphere ◽  
History Of ◽  
Time Variations

Fundamental to the understanding of high-latitude ionospheric behaviour is an appreciation of the convection electric field and its consequences. This electric field drives a number of processes which directly influence the plasma, including vertical ion drifts, Joule heating and enhanced neutral air velocities. Particle precipitation regions are closely connected with convection boundaries. Universal time variations can, in many cases, be directly related to the diurnal variation of the convection electric field in the geographical frame. Convection also has a profound influence on the interpretation of observations, because understanding why plasma densities have their observed characteristics requires knowledge of the past history of the observed plasma. This past history is determined by the convection electric field, as it transports plasma between regions of differing dominant plasma processes. Where reasonable estimates of the convection electric field exist, numerical models of the ionosphere seem capable of reproducing the characteristics of observed plasma behaviour. This is demonstrated by using the European incoherent-scatter facility’s observations for days for which such estimates are available.

scholarly journals The relationship between electric fields, conductances and currents in the high-latitude ionosphere: a statistical study using EISCAT data

1999 ◽  
Vol 17 (1) ◽  
pp. 43-52 ◽  
Author(s):  
J. A. Davies ◽  
M. Lester
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
High Latitude ◽  
Statistical Study ◽  
Field Vector ◽  
Relative Contribution ◽  
High Latitude Ionosphere ◽  
The Times ◽  
The Relationship ◽  
Uhf Radar

Abstract. The relationship between electric fields, height-integrated conductivities and electric currents in the high-latitude nightside electrojet region is known to be complex. The tristatic nature of the EISCAT UHF radar facility provides an excellent means of exploring this interrelationship as it enables simultaneous estimates to be made of the full electric field vector and the ionospheric Hall and Pedersen conductances, further allowing the determination of both field-perpendicular electric current components. Over 1300 h of common programme observations by the UHF radar system provide the basis of a statistical study of electric fields, conductances and currents in the high-latitude ionosphere, from which preliminary results are presented. Times at which there is significant solar contribution to the ionospheric conductances have been excluded by limiting the observations according to solar zenith angle. Initial results indicate that, in general, the times of peak conductance, identified from the entire set of EISCAT observations, do not correspond to the times of the largest electric field values; the relative contribution of ionospheric conductance and electric field to the electrojet currents therefore depends critically on local time, a conclusion which corroborates work by previous authors. Simultaneous measurements confirm a tendency for a decrease in both Hall and Pedersen conductances to be accompanied by an increase in the electric field, at least for moderate and large electric field value, a tendency which is also identified to some extent in the ratio of the conductances, which acts as an indicator of the energy of precipitating particles.Key words. Ionosphere (auroral ionosphere; electric fields and currents)

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