DNA Project 609 Radar: Auroral Backscatter Measurements.
Final rept. 31 Jan 74-30 Sep 75,
STANFORD RESEARCH INST MENLO PARK CALIF
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This report summarizes the research results obtained from auroral backscatter studies using the DNA 609 radar system located at Homer, Alaska. The primary purpose of the backscatter studies was to improve understanding of the auroral-clutter-producing mechanism. Most of the results are based on coordinated experiments utilizing the 398-MHz phased-array radar at Homer, the SRIDNA incoherent-scatter radar at Chatanika, and other complementary auroral measurement techniques. It was found that the problem can be most effectively approached by seeking both microscale and macroscale relationships--i.e., the relationships of local plasma parameters within the radar scattering volume producing auroral clutter, and the relationships of the large-scale auroral and magnetospheric conditions to the spatial distribution of auroral clutter, respectively. The results include the following 1 Diffuse auroral clutter is apparently not produced by primary plasma waves generated by the Buneman-Farley two-stream instability. 2 The mechanism does not, however, appear to be unlike the quasilinear gradient-drift instability model proposed by Sudan et al. 1973, which can be driven by the primary two-stream waves. 3 There is a threshold electric field strength of 30 mVm associated with the occurrence of 398-HMz diffuse auroral clutter. 4 The diffuse auroral clutter is closely associated with the auroral electrojets. 5 The evening diffuse auroral clutter is closely associated with downward field-aligned currents. 6 Discrete auroral clutter is closely associated with the discrete visual aurora.
- Atmospheric Physics
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation