Spectroscopic Studies of Limb Spicules. I. Radial and Turbulent Velocities

Abstract

We made high-resolution spectroscopic observations of limb-spicules in H-alpha using the Vertical Spectrograph of Domeless Solar Telescope at Hida Observatory. While more than half of the observed spicules have Gaussian line-profiles, some spicules have distinctly asymmetric profiles which can be fitted with two Gaussian components. The faster of these components has radial velocities of 10 - 40 km/s and Doppler-widths of about 0.4 A which suggest that it is from a single spicule oriented nearly along the line-of-sight. Profiles of the slower components and the single-Gaussian type show very similar characteristics. Their radial velocities are less than 10 km/s and the Doppler-widths are 0.6 - 0.9 A. Non-thermal "macroturbulent" velocities of order 30 km/s are required to explain these width-values.

13 pages, 12 figures, to be published in Publications of the Astronomical Society of Japan

References in corpus (2)

• Limb Spicules from the Ground and from Space
• Spicule Dynamics over Plage Region

Cited by in corpus (5)

• Revision of Solar Spicule Classification
• Role of Longitudinal Waves in Alfvén-wave-driven Solar Wind
• Spectroscopy at the solar limb: I. Average off-limb profiles and Doppler shifts of Ca II H
• Spectroscopy at the solar limb: II. Are spicules heated to coronal temperatures ?
• Dark off-limb gap: manifestation of temperature minimum and dynamic nature of the chromosphere