ИСТИНА

The PAIPS (Pulsating Aurora Imaging System) is a stereometric system of imaging photometers and spectrometers placed in two geophysical observatories (Verkhnetulomskaya and Lovozero) separated by 153 km. The system has been operating since fall 2021 and provides measurements of auroral emissions spatiotemporal structure with high temporal resolution (1 ms). Over the course of four seasons of the project's operation, a database of pulsating aurorae (PsA) was created and analysed. A stereometric method for estimating PsA altitudes based on per-pixel signal frequency analysis was developed and implemented. Emission altitudes of PsA range from 92.4 to 104 km. A new type of auroral emission — optical microbursts (OMB) — was discovered. OMBs are bright short-lived optical flashes with a characteristic duration of about 100 ms, occurring in groups lasting from seconds to hours. Over 4 seasons, 102 OMB series were detected. OMBs predominantly occur in the evening sector during the recovery phase of geomagnetic storms or sub-storms, with rare exceptions. Satellite charge particle detectors data analyses demonstrate that OMBs are associated with regions of increasing electron fluxes >100 keV within or at the polar boundary of the outer radiation belt. A spectrometric method for altitude estimation was developed, based on intensity ratios of molecular nitrogen lines and bands. Detector responses to nitrogen emission spectra were simulated for electron energies from 1 keV to 4 MeV. Comparing model and experimental data yielded OMB emission altitudes and precipitating electron energies around 100 keV. Various algorithms for selecting and reconstructing track events from imaging detectors were developed. Several tracks similar to those expected from EAS were found in PAIPS data. Confirming their EAS origin would enable widespread use of small fluorescent telescopes for studying cosmic rays at EeV energies, including in the future Taiga-100 experiment. The project intends to conduct further investigations into rapid auroral emission phenomena, including OMBs, pulsating aurora, and flickering aurora. To this end, the network of observation stations will be expanded to subauroral and polar regions (Barentsburg and Krasnoe Ozero). New photometric and spectrometric equipment will be developed, more spectrometric channels will be added.The project encompasses the development of an online software platform designed for simulating and computing optical emissions induced by high-energy particle precipitation. This platform accommodates both localized events and phenomena spanning the entire auroral oval, while providing compatibility with theoretical models and empirical spectra of precipitation fluxes. The work was supported by the Russian Science Foundation grant no. 22-62-00010 (https://rscf.ru/project/22-62-00010/).