During times of high solar activity flares and coronal mass ejections (CMEs) occur close in time, often even concurrently, and it might be difficult to recognize their source areas. Release of a CME on the far side of the Sun (STEREO A and B observations). The far side eruption stemmed from an area near W180. Based on a current paper: S. Pohjolainen, N. Talebpour Sheshvan, and C. Monstein: Separating the impacts of earthside and far side solar occasions.
During times of high solar activity flares and coronal mass ejections (CMEs) happen close in time, sometimes even concurrently, and it might be challenging to identify their source regions. Especially quick CMEs that are observed as propagating fronts high in the corona, can originate from a region on the Earth-facing side, or from the far side. To identify their origins and instructions of proliferation, one requires to do a mindful analysis that consists of observations from both sides. Comparing imaging with radio spectral data can tell if, and where, transients produce propagating shock waves.
We performed a case research study on a series of occasions that included a GOES X-class flare connected with an EUV wave, a metric type II burst, a halo-type CME, and an interplanetary (IP) type II burst, to learn if they were produced by simply one occasion. Doubts occurred from the fact that the estimated height-times of the transients did not match well.
Imaging from the far side by STEREO A and B instruments, revealed another eruption and a possible source for the CME. We computed source heights for the metric and IP type II bursts, and compared them with the CME heights observed from all views.
Release of a CME on the far side of the Sun (STEREO A and B observations). The far side eruption stemmed from an area near W180. An X-class flare on the earthside stemmed from an active area at E15.
Figure 2. Measured and computed heights of all propagating structures. For flares and filament eruption start times are revealed.
Our conclusion is that the X-class flare, followed by the EUV wave, caused the metric type II burst and a plasmoid ejection that got superposed on the halo CME structures. The behind eruption produced the halo CME and the IP type II burst. The metric and IP type II bursts were not connected, but were produced by separate propagating shock waves.
Based on a current paper: S. Pohjolainen, N. Talebpour Sheshvan, and C. Monstein: Separating the impacts of earthside and far side solar events. 72, Issue 9, 1 November 2023, Pages 4074-4081.