Plasma perturbations HF‐induced in the topside ionosphere

Abstract

Three plasma perturbations induced by SURA HF (high‐frequency) heating have been selected and analyzed in detail with the DEMETER satellite observing data by instruments of Langmuir probe and ion analyzer. Some common features are revealed, such as (1) electron density and electron temperature both increased during the heating period; (2) both O+ density and ion temperature also increased generally, while H+ varied negatively with O+ density; (3) the ions were accelerated in upward and northward directions, resulting from the thermal pressure gradient, which also caused the variations in ULF (ultralow‐frequency) electric field due to trueV⇀×trueB⇀ effects; and (4) the simulation results verify the electron density and temperature enhancement at the topside ionosphere due to the ohmic heating process and thermal self‐focusing instability over the heating region, which is consistent with the observing phenomena by the DEMETER satellite.

Overview of APEX Project Results

“…The ballistic transport mechanism was suggested by the authors to explain detection of increased noise at frequencies around 6 MHz from PRS-3 data while the IK-25 satellite was magnetically connected to the heated part of the ionosphere. Oraevsky et al (1998a) reported on similar results for the APEX and CORONAS satellites and the SURA ionospheric heating facility, more recently the experiment was repeated with the DEMETER satellite and the SURA heater (Zhang et al, 2016).…”

The Electromagnetic Emissions and Plasma Modulations at Middle Latitudes Related to SURA‐CSES Experiments in 2018

“…With the detected PWs, some small‐amplitude modulations simultaneously occurred in Ne and Te at the same region covered by PWs. It is difficult to define that Ne and Te increased or decreased in total trend during both experiments, unlike some cases between SURA‐DEMETER and HAARP‐DEMETER with clear increase in Te and Ne together under overdense heating condition (Zhang et al, 2016). So in both cases with underdense heating condition on 21 and 31 August, we do not see the formation of ducts induced by SURA, just as those experiments stated in SURA‐SWARM (Frolov et al, 2018).…”

“…SURA, as the old HF heating facility, has been operated since 1981. Many active experiments were conducted at SURA, including DEMETER, DMSP, CASSIOPE/e‐POP, and SWARM satellites (Frolov et al, 2008a, 2008b, 2016, 2018; James et al, 2017; Zhang et al, 2016), in which many related phenomena have been studied such as conditions for determining the formation of artificial ducts, an influence of pumping modes on turbulence features, HF heating mechanisms, and pumping wave (PW) ray tracing.…”

Chinese ionospheric investigations in 2016–2017

“…Zhang XM et al (2016) studied plasma perturbations induced by high frequency (HF) radio waves. By using experiment results between the DEMETER satellite and SURA heating facility in Russia, they found some common features in plasma parameters at topside ionosphere related to HF radio wave heating process, in which T e , N e and N i (O + ) increase while ions are accelerated upward and cause perturbations in ULF electric field.…”