Abstract In this paper theoretical predictions and EISCAT observations of vertical plasma transport at high latitudes are reviewed. It is pointed out that, even if the direction of the geomagnetic field departs from vertical by 10° to 15° only, this tilt is sufficient to create significant vertical plasma flow in the presence of auroral electric fields or horizontal neutral winds. One can estimate that vertical speeds due to electric fields are capable to cause observable deformation of plasma density even in the E-region. The electric field can move plasma upwards or downwards at all altitudes, but if its direction is proper, it may also drive plasma towards a certain height (both from above and below) or away from a certain height. Thus the electric field can both shift the E-region density profile in vertical direction and deform its shape. In addition, the electric field is able to generate a sporadic E-layer without any help of the neutral wind. In EISCAT experiments vertical velocities of the order of 50 m/s have been observed at E-region altitudes. Sometimes this flow can be ascribed to electric field only; on other occasions the effect of neutral wind is clearly visible. It is pointed out that the wind shear mechanism is capable of generating sporadic E-layers not only at mid-latitudes but also within the auroral region. In practice, ion-neutral collision frequency profiles can be inferred from electric field-induced vertical plasma velocities.
Vertical plasma transport due to electric fields and neutral winds in the auroral ionosphere
Advances in Space Research ; 10 , 6 ; 297-305
1989-01-01
9 pages
Article (Journal)
Electronic Resource
English
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