New Observational Projects in New Zealand for Verification of Radiation Belt Loss Processes in the Deep Inner Magnetosphere: Instrumentation and Initial Results

This paper describes the instrumentation of, and the first results from, an upper atmospheric observation project conducted in New Zealand. We operate an all-sky aurora camera and a 64-Hz sampling induction magnetometer at Middlemarch, as well as 1-Hz sampling fluxgate magnetometers which have been operative at three stations in New Zealand, Middlemarch, Eyrewell and Te Wharau. Green and red auroras respectively corresponding to the 557.7 nm and 630.0 nm emissions were observed on the night of 5 Aug 2019. Pc1 pulsations were observed in the frequency range of ~0.2–1 Hz before and after a small (minimum Dst = –40 nT) geomagnetic storm during 4–6 October 2020. Before the geomagnetic storm, Pc1 pulsations with several center frequencies were observed regardless of local time. During the recovery phase, an IPDP (interval of pulsations of diminishing period) type of Pc1 and subsequent four intervals Pc1s were detected. The Ionospheric Alfvén Resonator (IAR) was also identified with spectral resonance structures during this magnetic storm. Lower harmonic modes of IAR were present throughout the local nighttime, but higher harmonic modes with frequency of 5– 15 Hz seemed to disappear at the onset time of substorms. This is the first report of IAR at such a high frequency range and this is the first IAR observation in the southern hemisphere. Examples of applying cross-phase analysis to observation data of fluxgate magnetometers are also given.