The H_α surges and EUV jets from magnetic flux emergences and cancellations

National Astronomical Observatories/Yunnan Observatory, CAS, Kunming 650011, PR China e-mail: jyc@ynao.ac.cn

Received: 1 August 2005
Accepted: 1 February 2007

Abstract

We analyzed multi-wavelength observations of three surges with a recurrent period of about 70 min in H_α, EUV, and soft X-ray, which occurred in the quiet-sun region on 2000 November 3. These homologous surges were associated with small flares at the same base, but their exact footpoints were spatially separated from the flare. Each surge consisted of a cool H_α component and a hot, EUV or soft X-ray component, which showed different evolutions not only in space but also in time. The EUV jets had slightly converging shapes, underwent more complicate development, showed clearly twisting structures, and appeared to open to space. The H_α surges, however, were smaller and only traced the edges of the jets. They always occurred later than the jets but had dark EUV counterparts appearing in the bright jets. These surge activities were closely associated with two emerging bipoles and their driven flux cancellations at the base region, and were consistent with the magnetic reconnection surge model. The possible cause of the delay between the surges and jets, of the dark structures in the jets are discussed, along with the possible role of flux cancellations in generation of these surges.