skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Increase in the Amplitude of Line-of-sight Velocities of the Small-scale Motions in a Solar Filament before Eruption

Abstract

We present a study on the evolution of the small-scale velocity field in a solar filament as it approaches the eruption. The observation was carried out by the Solar Dynamics Doppler Imager (SDDI) that was newly installed on the Solar Magnetic Activity Research Telescope at Hida Observatory. The SDDI obtains a narrowband full-disk image of the Sun at 73 channels from H α − 9.0 Å to H α + 9.0 Å, allowing us to study the line-of-sight (LOS) velocity of the filament before and during the eruption. The observed filament is a quiescent filament that erupted on 2016 November 5. We derived the LOS velocity at each pixel in the filament using the Becker’s cloud model, and made the histograms of the LOS velocity at each time. The standard deviation of the LOS velocity distribution can be regarded as a measure for the amplitude of the small-scale motion in the filament. We found that the standard deviation on the previous day of the eruption was mostly constant around 2–3 km s{sup −1}, and it slightly increased to 3–4 km s{sup −1} on the day of the eruption. It shows a further increase, with a rate of 1.1 m s{supmore » −2}, about three hours before eruption, and another increase, with a rate of 2.8 m s{sup −2}, about an hour before eruption. From this result we suggest that the increase in the amplitude of the small-scale motions in a filament can be regarded as a precursor of the eruption.« less

Authors:
;  [1]; ; ; ;  [2]
  1. Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Sakyo, Kyoto 606-8306 (Japan)
  2. Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)
Publication Date:
OSTI Identifier:
22654441
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; CLOUDS; DISTRIBUTION; EVOLUTION; MASS; PRECURSOR; SOLAR FLARES; SUN; TELESCOPES; VELOCITY

Citation Formats

Seki, Daikichi, Isobe, Hiroaki, Otsuji, Kenichi, Ishii, Takako T., Sakaue, Takahito, and Hirose, Kumi, E-mail: seki@kwasan.kyoto-u.ac.jp. Increase in the Amplitude of Line-of-sight Velocities of the Small-scale Motions in a Solar Filament before Eruption. United States: N. p., 2017. Web. doi:10.3847/2041-8213/AA7559.
Seki, Daikichi, Isobe, Hiroaki, Otsuji, Kenichi, Ishii, Takako T., Sakaue, Takahito, & Hirose, Kumi, E-mail: seki@kwasan.kyoto-u.ac.jp. Increase in the Amplitude of Line-of-sight Velocities of the Small-scale Motions in a Solar Filament before Eruption. United States. doi:10.3847/2041-8213/AA7559.
Seki, Daikichi, Isobe, Hiroaki, Otsuji, Kenichi, Ishii, Takako T., Sakaue, Takahito, and Hirose, Kumi, E-mail: seki@kwasan.kyoto-u.ac.jp. Mon . "Increase in the Amplitude of Line-of-sight Velocities of the Small-scale Motions in a Solar Filament before Eruption". United States. doi:10.3847/2041-8213/AA7559.
@article{osti_22654441,
title = {Increase in the Amplitude of Line-of-sight Velocities of the Small-scale Motions in a Solar Filament before Eruption},
author = {Seki, Daikichi and Isobe, Hiroaki and Otsuji, Kenichi and Ishii, Takako T. and Sakaue, Takahito and Hirose, Kumi, E-mail: seki@kwasan.kyoto-u.ac.jp},
abstractNote = {We present a study on the evolution of the small-scale velocity field in a solar filament as it approaches the eruption. The observation was carried out by the Solar Dynamics Doppler Imager (SDDI) that was newly installed on the Solar Magnetic Activity Research Telescope at Hida Observatory. The SDDI obtains a narrowband full-disk image of the Sun at 73 channels from H α − 9.0 Å to H α + 9.0 Å, allowing us to study the line-of-sight (LOS) velocity of the filament before and during the eruption. The observed filament is a quiescent filament that erupted on 2016 November 5. We derived the LOS velocity at each pixel in the filament using the Becker’s cloud model, and made the histograms of the LOS velocity at each time. The standard deviation of the LOS velocity distribution can be regarded as a measure for the amplitude of the small-scale motion in the filament. We found that the standard deviation on the previous day of the eruption was mostly constant around 2–3 km s{sup −1}, and it slightly increased to 3–4 km s{sup −1} on the day of the eruption. It shows a further increase, with a rate of 1.1 m s{sup −2}, about three hours before eruption, and another increase, with a rate of 2.8 m s{sup −2}, about an hour before eruption. From this result we suggest that the increase in the amplitude of the small-scale motions in a filament can be regarded as a precursor of the eruption.},
doi = {10.3847/2041-8213/AA7559},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 843,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}