Summary: A study of a macro-spicule and a transition region explosive event in a solar
M. D. Popescua
, L. D. Xiab
, D. Banerjeec
and J. G. Doylea
Armagh Observatory, Armagh, Northern Ireland
CAS Key Laboratory of Basic Plasma Physics, Univ. of Science and Technology of China, Hefei, Anhui, China
Indian Institute of Astrophysics, Bangalore, India
Aims. Spicules and the higher macro-spicules (jet-like structures seen at the solar limb) are believed to be the dominant
mechanism for mass ejection in the higher solar atmosphere outside active regions. But what is the connection between them
and other small-scale structures in the Sun's atmosphere, like for example transition region explosive events, is not known yet.
Methods. Our data are temporal series spectroheliograms of EUV emission lines from two ions (N IV 765 Å and Ne VIII 770 Å),
taken with the SUMER (Solar UV Measurements of Emitted Radiation) spectrograph on SoHO (the Solar and Heliospheric
Observatory). SUMER's good spatial, spectral and temporal resolution allowed us to have one of the most detailed studies of
these small-scale structures over a range of transition region temperatures.
Results. Our study reveals that a macro-spicule seen off-limb looks similar to a transition region explosive event, especially