The morphological comparison and analysis of coronal green line

The coronal is the origins of large-scale solar activity and disastrous space weather, it contains extremely rich information and various physical processes. The coronal loop is a kind of bright structure with hot plasma which is bounded by magnetic field in the coronal, it is a good reflection of the magnetic structure that we can hardly observe directly. It is also the energy channel between the photosphere and coronal, and the study of coronal loop is helpful for us to understand the magnetic line foot movement.

The coronal green line monitoring: a traditional but powerful tool for coronal physics

The particular environment with high temperature and low plasma density in the corona results to the formation of some forbidden emission lines, in which the well-known green line at 530.3 nm has been utilized to diagnose the corona for a few decades. For the green line, besides its contribution on revealing the long-term coronal cycles as well as their relationship to the other solar phenomena, it is also helpful to detect limb coronal waves and ejections originated from the lower corona which seems not to be paid close attention to. Suggestions are presented that we not only need to keep the green line observation as a routine task for current coronagraph observations, but need to develop larger coronagraphs with advanced technology.

Gnevyshev peaks in solar radio emissions at different frequencies

Sunspots have a major 11-year cycle, but the years near the sunspot maximum show two or more peaks called GP (Gnevyshev Peaks). In this communication, it was examined whether these peaks in sunspots are reflected in other parameters such as Lyman-α (the chromospheric emission 121.6 nm), radio emissions 242–15 400 MHz emanating from altitude levels 2000–12 000 km, the low latitude (+45° to −45°) solar open magnetic flux and the coronal green line emission (Fe XIV, 530.3 nm). In the different solar cycles 20–23, the similarity extended at least upto the level of 609 MHz, but in cycle 22, the highest level was of 242 MHz. The extension to the higher level in cycle 22 does not seem to be related to the cycle strength Rz(max), or to the cycle length.