Reexamining X‐mode suppression and fine structure in artificial E region field‐aligned plasma density irregularities

摘要: [1] Artificial field-aligned plasma density irregularities (FAIs) were generated in the E region of ionosphere above High Frequency Active Auroral Research Program facility during campaigns May and August 2012 observed using a 30 MHz coherent scatter radar imager Homer, Alaska. The purpose this ionospheric modification experiment was to measure threshold pump power required excite thermal parametric instabilities by O-mode heating investigate suppression FAIs simultaneous X-mode heating. We find that for irregularity excitation consistent with theoretical predictions increased approximately factor 2 when present. A modified version Another Model Ionosphere (SAMI2) model used simulate experiments suggested increase entirely due enhanced D absorption associated Additionally, remarkable degree fine structure possibly caused natural gradient drift instability heater-modified volume performed geomagnetically active conditions.