Ganyu Observation Station, PMO, CAS
Ganyu solar observing station is located at Ganyu county, Jiangsu province. It is very near Lianyungang city, one of the most important city in north Jiangsu province. Because of its latitude, the climate condition of Ganyu county is similar to the one in North China. It can be called a Sun shine county of Jiangsu province. In most years, the Sun shine hours exceed 2200. Also, seeing condition around the observing site can be about 1 arcsec.
We own a 26 cm aperture telescope in the observing station, which is called Halpha solar fine structure telescope. The telescope is equitorial two-tube, one tube is for Halpha observation, while another is for white-light observation. With the state-of-art birefringent filter, we observe the solar chromosphere at 656.3 nm, with the scientific aim of investigating the fine physical processes of triggering and energy releasing of solar flares, filament eruptions and other activities like chromospheric surges and jets. With white light, we observe simultaneously sunspots in active regions, studying the relationship between evolution of sunspots and solar activities. This kind of observation is quite useful for forcasting solar activities. The fov of the tescope is 4'x6'.
During the solar 22nd and 23rd maximum years, we achieved following scientific results with observation made at Ganyu: the investigation of spiral filaments, the mechanisms of Ellerman Bombs, the merge of large sunspot groups, magnetic structure of large delta-type sunspots, and magnetic reconnection in the lower solar atmosphere. It is worth mention that we discovered the contraction process of flaring loops caused by magnetic reconnection between highly-sheared flux ropes. The contraction consists of two aspects: converging motion of flare footpoints and descending motion of looptop sources. Traditional picture of expansion of flaring loops can be seen only after the contraction. Further investigations suggest that over half flares have this kind ocontraction-expansion process.
Face with the slowly coming 24th maximum years, we will focus our observation at high-caence imaging of solar flares (20-30 fps). Combined with high temporal and spatial observations made by world-wide ground and space solar observing facilities, we aim at studying fine temporal structures of solar flare emissions, which will hopefully lead to the better understanding of solar elememtary bursts and, thus, add our understanding to magnetic reconnection that occurs everywhere in our Universe.