Consistent quasi-periodic variations of the geomagnetic pulsation level and doppler frequency shift of decametric radio waves aspect-scattered by artificial field-aligned ionospheric irregularities

Abstract

We present the results of experimental studies of consistent quasi-periodic variations of the geomagnetic-pulsation level and effective Doppler frequency shift of decametric radio waves aspectscattered by artificial field-aligned ionospheric irregularities. For processing of signals, we used a system spectral analysis and a correlation analysis. It is shown that quasi-periodic variations of the effective Doppler frequency shift are caused by geomagnetic-field pulsations with an amplitude of 0.5-1.0 nT and a period of 50-150 s. Estimated amplitudes of the quasi-periodic and aperiodic drift velocities of the ionospheric irregularities appeared close to 5-10 and 15-30 m/s, respectively.

Drift Velocity of Small-Scale Artificial Ionospheric Irregularities According to a Multifrequency HF Doppler Radar. II. Observation and Modeling Results

“…Note that sometimes the drift velocity exceeds 1000 m/s or even reaches 3000 m/s. The errors δ of solution of the overdetermined system of equations (6) in [1] do not exceed their typical values 15-20%, i. e.,…”

“…The following should be borne in mind when the drift velocity of irregularities is estimated from the Doppler measurements of scattered signals. Along with the Doppler frequency shift caused by a regular drift of irregularities, quasiperiodic variations of the frequency shift, which are related to propagation of intense magnetohydrodynamic (MHD) waves from the magnetosphere, can be observed [4][5][6].…”

Geomagnetic Pulsation Amplitude and Spectrum Variations Accompanying the Ionospheric Heating by High-Power Radio waves from the Sura Facility

“…However, the detection procedures and computation tools did not permit us to convincingly single out the desired effects. In one of the last experiments [25], we also failed to prove the possiibility of generation of geomagnetic pulsations with the SURA heating facility, which, most probably, was due to its low effective radiated power P G ≈ 40 MW. In the experiments considered in this paper we recorded artificial geomagnetic pulsations when the power P G was 70-150 MW.…”