Ground-Based and Satellite Observations of the SAR Arc in the MLT Evening Sector at the Beginning of the Magnetic Storm on March 17, 2015

Stable auroral red (SAR) arcs are the result of the interaction of energetic ring current ions with the outer plasmasphere (plasmapause). The article analyzes the results of the observation of a SAR arc by an all-sky imager at Maimaga station (58 degrees CGMLat, 202 degrees CGMLon) with the simultaneous detection of the plasmapause and energetic ion fluxes by the Van Allen Probe B (VAP-B) satellite at the beginning of a large magnetic storm on March 17, 2015. The all-sky imager registered an intense SAR arc at corrected geomagnetic latitudes of 52 degrees-59 degrees in the MLT evening sector, starting from similar to 1116 UT (1926 MLT), during low auroral activity at IMFBz > 0. According to the VAP-B satellite, the plasmapause was at L similar to 3-4, and the inner boundary of energetic ion fluxes H+ and O+ was at L similar to 2.8-3.3 near the meridian of optical observations. The DMSP-F19 satellite measured the subauroral electron temperature peaks at 1014 and 1155 UT in the MLT evening sector. It is shown that the SAR arc mapped in this case the overlap region of plasmasphere dusk-bulge by the flux of energetic ring current ions after the beginning of the magnetic storm.