Transient Formation of Loops in the Core of an Active Region

We study the formation of transient loops in the core of the AR 11890. For this purpose, we have used the observations recorded by the Atmospheric Imaging Assembly (AIA) and the Interface Region Imaging Spectrograph (IRIS). For photospheric field configuration, we have used the line-of-sight (LOS) magnetograms obtained from the Helioseismic and Magnetic Imager. The transient is simultaneously observed in all the UV and EUV channels of AIA and the three slit-jaw images from IRIS. The coexistence of the transient in all AIA and IRIS SJI channels suggests the transient's multithermal nature. The transient consists of short loops located at the base of the transient, as well as long loops. A differential emission measure analysis shows that the transient has a clumpy structure. The highest emission observed at the base is within the temperature bin of log T = 6.65-6.95. We observe the longer loops at a similar temperature, albeit very feeble. Using LOS magnetograms, we conclude that the magnetic reconnection may have caused the transient. Our observations further suggest that the physics of the formation of such transients may be similar to those of typical coronal jets, albeit in different topological configurations. Such multiwavelength observations shed light on the formation of hot plasma in the solar corona and provide further essential constraints on modeling the thermodynamics of such transients.