INFLUENCE OF THE IONOSPHERE, MODIFIED BY POWERFUL OBLIQUE RADIOWAVES,ON HF RADIO-WAVE PROPAGATION

Variations of HF probe radio wave parameters caused by the influence o n the ionosphere of oblique powerful HF radiowaves are analysed. The a nalysis is made on the data obtained from the original experiments car ried out on single-hop paths in the middle and subauroral latitudes. P owerful and probe waves with some difference in frequency were chosen near MUF and were transmitted in the same direction. The polar diagram s of both transmitting systems overlapped in both the horizontal and v ertical planes. The results obtained indicate that the ionospheric pla sma parameters can be varied by powerful oblique HF radiowaves under c ertain geophysical conditions. (C) 1997 Elsevier Science Ltd.