Interhemispheric ionosphere-plasmasphere system shows a high sensitivity to the exospheric neutral hydrogen density: a caution of the global reference atmospheric model hydrogen density

This study explores the impact of the exosphere hydrogen (H) density on the ionosphere-plasmasphere system using a model whose key inputs are constrained by ionosphere observations at both ends of the magnetic field line with an L-value of 1.75 in the American longitudinal sector during a period with low solar and magnetic activities. This study is the first to be validated by ground-based and satellite data in the plasmasphere and both hemispheres. The main finding is that the entire ionosphere-plasmasphere system is very sensitive to the neutral hydrogen density in the lower exosphere. It was found that an increase in the H density by a factor of 2.75 from the commonly accepted values was necessary to bring the simulated plasma density into satisfactory agreement with Arase satellite measurements in the plasmasphere and also with DMSP satellite measurements in the topside ionospheres of the northern and southern hemispheres. A factor of 2.75 increase in the H density increases the simulated plasma density in the afternoon plasmasphere up to ∼80% and in the nighttime topside ionosphere up to ∼100%. These results indicate prominently that using the commonly accepted empirical model of the H density causes unacceptable errors in the simulated plasma density of the near-Earth plasma shells. We alert the space science community of this problem

Some aspects of developing a multipurpose radio system for monitoring the geospace

Hardware and software principles of building a multipurpose radio system for monitoring the geospace are considered. It is shown that Ettus Research USRP is the most suitable platform for such system. A structure of a multipurpose radio system for monitoring the geospace and developed software for VISCR2 ionosonde (based on USRP N200) as a part of this system are presented. The first results of testing new sowtware are shown

Performance Analysis of a Portable Low-Cost SDR-Based Ionosonde

This work presents a software-defined radio ionosonde (ISDR) developed at the Abdus Salam International Centre for Theoretical Physics (Italy) and the Institute of Radio Astronomy (Ukraine) and installed at the Ukrainian Antarctic Station in 2017. For the first time, the results of the long-term data comparison of the ISDR with the conventional ionosonde IPS-42 produced by KEL Aerospace are presented and discussed. The matching of the ionograms obtained during the whole year of 2021, as well as a comparison of the critical frequencies and virtual heights of F, E, and Es layers manually scaled from the ionograms showed that the ISDR has a similar level of performance to IPS-42. At the same time, the ISDR is a more versatile instrument that supports a bistatic operation, provides Doppler measurements and polarization information, and has a significantly lower cost and transmission power. Different configurations of the ISDR are considered. The basic configuration allows for using the ISDR as a conventional vertical ionospheric sounder. An enhanced configuration of the ISDR allows for oblique sounding, as well as polarization information that enables the O- and X-propagation modes of the ionospheric signal to be distinguished. The enhanced passive version of the ISDR was successfully tested onboard the research vessel “Noosfera” on distances up to 1,400 km from the transmitting ISDR