Eruption of a Million-Kelvin Warm Magnetic Flux Rope on the Sun

Solar magnetic flux rope (MFR) plays a central role in the physics of coronal mass ejections (CMEs). It mainly includes a cold filament at typical chromospheric temperatures (similar to 10,000 K) and a hot channel at high coronal temperatures (similar to 10 MK). The warm MFR at quiescent coronal temperatures of a million Kelvin is, however, rarely reported. In this study, using multiwavelength images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory and Extreme Ultraviolet Imager (EUVI) on board the Solar Terrestrial Relations Observatory-A, we present an eruption of a warm channel that represents an MFR with quiescent coronal temperatures (similar to 0.6-2.5 MK). On 2022 May 8, we observed the failed eruption of a hot channel, with the average temperature and emission measure (EM) of 10 MK and 1.1 x 1028 cm-5, using AIA high-temperature images in the active region (AR) 13007. This failed eruption was associated with a C8.2 flare, with no CME. Subsequently, we observed a warm channel that appeared in AIA and EUVI low-temperature images rather than in AIA high-temperature images. It then erupted and transformed into a semicircular shape. An associated C2.1 flare, along with the signatures of magnetic reconnection in AIA high-temperature images, were identified. Additionally, we observed a CME associated with this event. Compared with the hot channel, the warm channel is cooler and rarer with the average temperature and EM of 1.7 (1.6) MK and 2.0 x 1026 (2.3 x 1026) cm-5. All the results suggest an unambiguous observation of the million-Kelvin warm MFR that erupted as a CME and fill a gap in the temperature domain of coronal MFRs.