Abstract:
We analyze the eruption of a coronal plasma channel (CPC) and an overlying flux rope using Atmospheric Imaging Assembly/Solar Dynamic Observatory (AIA/SDO) and Solar TErrestrial RElations Observatory (STEREO)-A spacecraft data. The CPC erupted first with its low and very faint coronal signature. Later, above the CPC, a diffuse and thin flux rope also developed and erupted. The spreading CPC further triggered a rotating jet-like structure from the coronal hole lying to its northward end. This jet-like eruption may have evolved due to the interaction between spreading CPC and the open field lines of the coronal hole lying towards its northward foot-point. The CPC connected two small trans-equatorial coronal holes lying, respectively, in the northern and southern hemisphere on either side of the Equator. These eruptions were collectively associated with the stealth-type CMEs and CME associated with a jet-like eruption. The source region of the stealth CMEs lay between two coronal holes connected by a coronal plasma channel. Another CME was also associated with a jet-like eruption that occurred from the coronal hole in the northern hemisphere. These CMEs evolved without any low coronal signature and yet were responsible for the third strongest geomagnetic storm of Solar Cycle 24. These stealth CMEs further merged and collectively passed through the interplanetary space. The compound CME further produced an intense geomagnetic storm (GMS) with Dst index=−176nT. The z-component of the interplanetary magnetic field [Bz] switched to negative (−18nT) during this interaction, and simultaneous measurement of the disturbance in the Earth’s magnetic field (Kp = 7) indicates the onset of the geomagnetic storm. © 2019, Springer Nature B.V.
