ИСТИНА

Several scientific instruments operate simultaneously aboard the International Space Station (ISS), enabling investigations of the energetic radiation belt dynamics and their influence on the upper atmosphere. The astrophysical detectors CALET and MAXI, mounted on the Japanese experimental module, primarily study cosmic ray acceleration and gamma-ray bursts; however, CALET also measure electron fluxes at energies >1.6 MeV and >3.6 MeV, while MAXI's Radiation Belt Monitor (RBM) resolves electron fluxes (>0.3 MeV) at 1 s cadence. The "UV Atmosphere" (Mini-EUSO) telescope, deployed on the Russian segment of the ISS since 2019, features a 40° field of view, 490 cm2 aperture for high sensitivity, and 2.5 μs temporal resolution, facilitating detection of transient atmospheric emissions. While primarily targeting thunderstorm phenomena (ELVES, sprites, blue jets), but in high latitudes, it can register both pulsating aurorae (PsA) and recently discovered optical microbursts (OMB). However, such studies have not previously been conducted using this instrumentation. The ISS's ~52° inclination precludes auroral oval overflights every orbit, but pre-noon sector passes over the USA/Canada region become feasible during moderate-to-intense geomagnetic disturbances, when equatorward oval expansion occurs. Since 2019, more than 150 measurement sessions have been conducted, during each the ISS completes 6 to 10 orbits around Earth at different longitudes and periodically enters the Canadian sector. For all sessions, an analysis of the geophysical conditions, storm and substorm activity (SYM-H variation and AU/AL indices) was conducted. A dedicated database catalogs "UV Atmosphere" sessions with accompanying geomagnetic parameters: https://uhecr.sinp.msu.ru/mini-euso-sessions.html. Session 31 (11–12 January 2021) exemplifies optimal conditions: telescope operation over the Canadian sector at peak geomagnetic latitudes, with the polar orbit fully nightside. Substorm activity during the storm recovery phase positioned the auroral oval's equatorial boundary within the instrument's field of view, according to CARISMA magnetometer data. Distinct auroral signatures revealed dynamic fine-scale spatiotemporal structure at the equatorward oval edge, including equatorward expansion. Concurrent MAXI observations registered precipitating electrons (E > 300 keV), while CALET data (E > 1.6 MeV) showed no variations. This work was supported by Russian Science Foundation grant No. 22-62-00010 (https://rscf.ru/project/22-62-00010/). \