Observations of ionospheric modification by the Tromsø heating facility with the mobile diagnostic equipment of IZMIRAN

Exploring HF‐induced ionospheric turbulence by Doppler sounding and stimulated electromagnetic emissions at the High Frequency Active Auroral Research Program heating facility

“…Here f p = ( e 2 N / πm ) 1/2 , and f ce = eB /2 πmc are the electron plasma frequency and the electron cyclotron frequency, respectively, e and m are the electron charge and mass, N is the electron density, c is the speed of light, and B is the geomagnetic field strength. This corresponds to existing theoretical concepts confirmed by investigations of the HF‐pumped ionospheric volume by multifrequency Doppler sounding (MDS) at Sura and European Incoherent Scatter (EISCAT) heating facilities [ Vas ' kov et al ., ; Berezin et al ., ; Lobachevsky et al ., ; Shindin et al ., ], which have revealed plasma expulsion from the resonance regions.…”

Modification of the electron density profile near the upper hybrid layer during radio wave heating of the ionosphere

“…With the use of a Doppler diagnostic instrument, probe waves at eight frequencies slightly below the pump frequency were launched seven and a half seconds before the turn on of the high power heater wave. The spatial resolution in height due to this multiple‐frequency diagnostic was 0.1 km and the temporal resolution was 1 s. The details of the diagnostic technique can be found in [ Lobachevsky et al , 1992].…”

“… High frequency (HF) radio waves can modify the electron density profile of the ionosphere in the upper hybrid resonance region (UHR). The spatial and temporal development of this modification was investigated using a multi‐frequency Doppler diagnostic system at the TROMSØ facility [ Lobachevsky et al , 1992]. We present the results of the simulations of the density profile modification near the upper hybrid resonance height for the parameters relevant to the experiment and show that the spatio‐temporal development of the density modification is quantitatively modelled by the mode conversion and the radio wave heating. …”

Diagnostics of the HF-pumped ionospheric region using wide-band radio emission

“…This results in the formation of a SEE spectrum with complex multi-component structure. The most typical upper-hybrid components of the radiation are the negative maximum (Downshifted Maximum, DM) in the region of negative detunings with ∆f ≈ − (9)(10)(11)(12)(13)(14)(15)(16)(17)(18) kHz, its satellites (2DM and 3DM) for multiple detunings, the positive maximum (Upshifted Maximum, UM) with ∆f ≈ 7-15 kHz, which is mirror-opposite to the DM, but is not as intense, the broadband component (Broad Continuum, BC) with ∆f ≈ − kHz, and a less intense broadband structure (Broad Upshifted Structure, BUS) with ∆f ≈ 15-100 kHz. During pumping at frequencies higher than the electron cyclotron harmonics (f 0 nf ce ), the generation of a broad positive maximum (Broad Upshifted Maximum, BUM) with ∆f ≈ 15-250 kHz and intensity maximum for the detunings ∆f ≈ f 0 − nf ce is observed.…”

“…However, obtaining the dynamic structure of the electron number density perturbation region requires the development of new algorithms for experimental data processing (solution of integral equation (3)). At present, a data processing algorithm for a fairly coarse grid of separated and fixed frequencies of test waves has been debugged [8,9].…”