Observations of the Heating Experiments in the Polar Winter Ionosphere

Abstract

According to the analysis of the ISR observation data, the heating effects in polar winter ionospheric modification experiments carried out in January 2008 at Tromsø, Norway were studied. A clear disturbance effect is present under the O‐mode over‐dense heating conditions. The enhancement of the electron temperature is up to 60%~120%, extending from 150 km to 400 km. The disturbance of the electron density is not obvious, with a 12% maximum decrease. An 1~2 kHz increase at the acoustic frequency can be observed, and an enhancement in the peak‐to‐valley ratio of the ion line and sometimes its high‐order harmonics can be seen as well. The power of the ion line and plasma line has shown an overshoot effect, single‐humped, double‐humped and triple‐humped structures have appeared in the power profile of plasma line, and the enhancement in power amplitude of the plasma line decreases exponentially as the frequency increases.

Observations of the Heating Experiments in the Polar Winter Ionosphere III–Analysis in the Low Region

“…Based on the super-Gaussian incoherent scatter theoretical model, the LM arithmetic is used to inverse the ionospheric heating data at 10:08, 10:16, 10:24, 10:32, 10:40, 10:48, 10:56 on January 11th, 2008 at 100 km. The detailed description of the heating experiment is given by literature [15]. The heater was switched on/off every 4 min.…”

“…Combining Eqs. (14) and (15), the heating electric field can be deduced from non-Maxwellian index. The heating electric fields at different times are given in Fig.…”

“…And the increment of electron temperature is up to 55%. The more obvious effects can be seen in polar winter ionosphere modification experiments carried out in January 2008, and the increment of electron temperature is up to 121% [15] . However, all the obvious characteristics of ionospheric heating are only observed in high ionosphere, and it is difficulty to find the heating effect in the low region, which is due to the limitation of the incoherent scatter theory.…”

Progress in polar upper atmospheric physics research in China

“…It was concluded that the non-Maxwellian factor should be considered in inversion of incoherent scatter power during ionosphere heating. Xu et al [111] examined heating effects in polar winter ionospheric modification experiments of January 2008 at Tromsø, Norway. Results showed a clear disturbance effect under O-mode overdense heating conditions.…”

Application of 20‐Moment Approximation for Ion Velocity Distribution Function in Calculations of Incoherent Scatter Spectra

“…Xu, Wu, Xue et al [28,29] recently have studied the 13-moment approximation of ion velocity distribution to calculate incoherent scatter radar spectra. The first artificial heat ionosphere data of China was analyzed by Xu et al [30] . The ion temperature anisotropies was characterized by the stress tensor and the heat flow, and the 20-moment approximation for the ion distribution function given by Barakat et al contain the stress tensor and the heat flow term [31] .…”