阿部 琢美

The measurement of virtual height of the sporadic E layer (h'Es) is very sensitive to the type of ionosonde used and the calibration processes. The ionosondes used by the national institute of communication and technology (NICT) has changed several times in the past, resulting in large differences in h'Es before and after the change. We propose a simple method to calibrate h'Es. We used the data of ionosonde observations at four stations, i.e., Wakkanai (45.16 degrees N, 141.75 degrees E), Tokyo (35.71 degrees N, 139.49 degrees E), Yamagawa (31.20 degrees N, 130.62 degrees E), Okinawa (26.68 degrees N, 128.15 degrees E) to calibrate the latest ionosondes VIPIR2, which were installed in May 2017. We carried out the analysis by applying the double-reflection method to the original ionogram images between 2017 and 2021. By developing an automated image detecting algorithm, we were able to process a large amount of data and achieve a calibration with high accuracy. As a result, it was found that the current VIPIR2 data had an offset of 26-28 km.

One of the first instruments used to monitor laboratory plasmas was the Langmuir probe (LP). This instrument is still one of the key sensors in laboratory plasma investigations. With the access to space, the first sounding rockets with Langmuir Probes were flown in 1946-1947; followed with Langmuir probes on satellites from the early 1960s and on Pioneer Venus Orbiter and subsequent interplanetary probes starting in the 1970s. This paper summarizes some of the experiences of using Langmuir probes over the last 75-years in space, what issues have been encountered, and how to overcome different known effects unique to space flight measurements. This work was done through a number of workshops attended by a number of instrument team members and supported by the ISSI organisation.

In the White Paper, submitted in response to the European Space Agency (ESA) Voyage 2050 Call, we present the importance of advancing our knowledge of plasma-neutral gas interactions, and of deepening our understanding of the partially ionized environments that are ubiquitous in the upper atmospheres of planets and moons, and elsewhere in space. In future space missions, the above task requires addressing the following fundamental questions: (A) How and by how much do plasma-neutral gas interactions influence the re-distribution of externally provided energy to the composing species? (B) How and by how much do plasma-neutral gas interactions contribute toward the growth of heavy complex molecules and biomolecules? Answering these questions is an absolute prerequisite for addressing the long-standing questions of atmospheric escape, the origin of biomolecules, and their role in the evolution of planets, moons, or comets, under the influence of energy sources in the form of electromagnetic and corpuscular radiation, because low-energy ion-neutral cross-sections in space cannot be reproduced quantitatively in laboratories for conditions of satisfying, particularly, (1) low-temperatures, (2) tenuous or strong gradients or layered media, and (3) in low-gravity plasma. Measurements with a minimum core instrument package (< 15 kg) can be used to perform such investigations in many different conditions and should be included in all deep-space missions. These investigations, if specific ranges of background parameters are considered, can also be pursued for Earth, Mars, and Venus.