Solar spicules and macrospicules observed by SUMER

Abstract

Motivated by recent observations of spicules and macrospicules in the far-ultraviolet (FUV) wavelength range with the Solar Ultraviolet Measurements of Emitted Radiation spectrograph (SUMER) on the Solar and Heliospheric Observatory (SOHO), a generation mechanism for spicules and macrospicules is outlined which deviates significantly from most of the previous concepts. The important aspect is that the spicule propagation is not strictly aligned along the local magnetic field direction and that there is a close association with explosive events. It is suggested that the chromospheric material will be carried up by the relaxing magnetic field following a field line reconnection. Some of the consequences for spicules and other features of the quiet- Sun (QS) atmosphere will be discussed, such as the average red shift of FUV emission lines in the transition region (TR) and polar plume formation in coronal holes (CHs).