Kink-and-Disconnection Failed Eruption in 3D

Abstract

We present a case study of a failed eruption that accompanied an M1.5 GOES class solar flare. It was observed by STIX onboard Solar Orbiter, HXI onboard the Advanced Space-based Solar Observatory, AIA onboard Solar Dynamics Observatory, and WAVES onboard the STEREO-A. The important input is from stereoscopic hard X-ray (HXR) observations obtained by HXI and STIX, whose vantage points were separated by $31.5^{\circ }$ 31.5 ∘ , allowing us to unfold the 3D geometry of the event. The eruption was a two-phase event. First, it started with the rope helical kink and then was slowed down, but with the structure still unstable, it erupted two minutes later due to ongoing reconnection in the interacting legs of the kinked structure. A Type III burst was observed in association with the eruption, indicating the acceleration of semirelativistic electrons into the heliosphere. During the second phase, a hot cloud was disconnected and confined in the overlying magnetic field, where the overlying loops connected two adjacent active regions. The estimated and corrected for real geometry velocities are in the range of 385 – 400 km s−1, whereas acceleration reached 4.78 – 6.33 km s−2. These extreme values are much more demanding from a perspective of conditions that are needed to stop the eruption. Images obtained simultaneously by HXI and STIX located in different vantage points showed that flare-related sources are not lying along a normal to the solar surface. The understanding of the eruption analyzed here has been highly enriched thanks to the stereoscopic information about HXR source locations.