Studying The Small-Scale Structure Of A Polarization Jet During The April 20, 2018 Geomagnetic Storm

In this work, we study the small-scale structure of a polarization jet in the subauroral region during the April 20, 2018 geomagnetic storm. We report measurement results of plasma parameters inside the polarization jet with a maximum sampling rate of up to 1 kHz, obtained with Langmuir probes installed on the NorSat-1 microsatellite. The study establishes the presence of temperature and electron density inhomogeneities inside the polarization jet with spatial dimensions of tens to hundreds of meters. The previously known features of the polarization jet evolution have been confirmed. We have also found that the distribution of the electron temperature inside the jet forms two separate peaks as the geomagnetic activity develops during the storm.