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Title: ON THE MULTI-THREADED NATURE OF SOLAR SPICULES

A dominant constituent in the dynamic chromosphere is spicules. Spicules at the limb appear as relatively small and dynamic jets that are observed to stick out everywhere. Many papers emphasize the important role spicules might play in the energy and mass balance of the chromosphere and corona. However, many aspects of spicules remain a mystery. In this Letter, we shed more light on the multi-threaded nature of spicules and their torsional component. We use high spatial, spectral, and temporal resolution observations from the Swedish 1 m Solar Telescope in the Hα spectral line. The data target the limb, and we extract spectra from spicules far out from the limb to reduce the line-of-sight superposition effect. We discover that many spicules display very asymmetric spectra with some even showing multiple peaks. To quantify this asymmetry, we use a double-Gaussian fitting procedure and find an average velocity difference between the single-Gaussian components to be between 20 and 30 km s{sup –1} for a sample of 57 spicules. We observe that spicules show significant substructure where one spicule consists of many ''threads''. We interpret the asymmetric spectra as a line-of-sight superposition of threads in one spicule and therefore have a measure for a perpendicular flowmore » inside spicules that will be important for future numerical models to reproduce. In addition, we show examples of λ – x slices perpendicular across spicules and find spectral tilts in individual threads, providing further evidence for the complex dynamical nature of spicules.« less
Authors:
; ;  [1]
  1. Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway)
Publication Date:
OSTI Identifier:
22364492
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; CHROMOSPHERE; JETS; MASS BALANCE; RESOLUTION; SOLAR PROMINENCES; SUN; TELESCOPES; VELOCITY; VISIBLE RADIATION