科研之友
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摘要
Origins and characteristics of small-scale plasma irregularities in the polar ionosphere are investigated using a dual radar setup in which the E region is probed from opposite directions by two Super Dual Auroral Radar Network facilities at the McMurdo and Dome Concordia Antarctic stations. In certain time intervals, velocity agreement is observed when velocities are compared at the same physical location in the horizontal plane. Such an agreement is widely expected if velocity at a given location is largely controlled by the convection electric field. In other cases, however, velocity agreement is unexpectedly observed when measurements are considered at the same slant range (distance along the radar beam) for both radars. This implies that it is not the electric field at a given location that is a controlling factor. Raytracing results show that the same range agreement may be explained for certain E region density conditions when echo altitude increases with radar range. Backscatter observations under generally unfavorable conditions for irregularity generation and the critical role of propagation conditions in the polar cap are discussed. The observed E region velocity in the polar cap is demonstrated to depend indirectly on the plasma density distribution, which is important for establishing the fundamental dependence on the convection electric field.
- 出版日期2015-10
