A New Solar Imaging System for Observing High-Speed Eruptions: Solar Dynamics Doppler Imager (SDDI)

Ichimoto, Kiyoshi; Ishii, Takako T.; Otsuji, Kenichi; Kimura, Goichi; Nakatani, Yusuke; Kaneda, Norimasa; Nagata, Shinji; Ueno, S.; Hirose, Katsuyuki; Cabezas, Denis P.; Morita, Satoshi

doi:10.1007/s11207-017-1082-7

Cited by 44 publications

(21 citation statements)

References 14 publications

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“…However, they are basically imaging observations to record structural changes projected onto the sky plane seen from the Earth, with some exceptions. On the other hand, some ground-based observatories are obtaining Doppler velocity data in Ha (e.g., Ichimoto et al, 2017). The combination of the two-dimensional images and Doppler data gives the three-dimensional velocities of eruptive features.…”

Section: Introductionmentioning

confidence: 99%

Synoptic solar observations of the Solar Flare Telescope focusing on space weather

Hanaoka

Sakurai

Otsuji

et al. 2020

J. Space Weather Space Clim.

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The solar group at the National Astronomical Observatory of Japan is conducting synoptic solar observations with the Solar Flare Telescope. While it is a part of a long-term solar monitoring, contributing to the study of solar dynamo governing solar activity cycles, it is also an attempt at contributing to space weather research. The observations include imaging with filters for H$\alpha$, Ca K, G-band, and continuum, and spectropolarimetry at the wavelength bands including the He I 1083.0 nm / Si I 1082.7 nm and the Fe I 1564.8 nm lines. Data for the brightness, Doppler signal, and magnetic field information of the photosphere and the chromosphere are obtained. In addition to monitoring dynamic phenomena like flares and filament eruptions, we can track the evolution of the magnetic fields that drive them on the basis of these data. Furthermore, the magnetic field in solar filaments, which develops into a part of the interplanetary magnetic cloud after their eruption and occasionally hits the Earth, can be inferred in its pre-eruption configuration. Such observations beyond mere classical monitoring of the Sun will hereafter become crucially important from the viewpoint of the prediction of space weather phenomena. The current synoptic observations with the Solar Flare Telescope is considered to be a pioneering one for future synoptic observations of the Sun with advanced instruments.

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Section: Introductionmentioning

confidence: 99%

Synoptic solar observations of the Solar Flare Telescope focusing on space weather

Hanaoka

Sakurai

Otsuji

et al. 2020

J. Space Weather Space Clim.

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“…There are several observational methods from the ground such as a coronagraph, a magnetogram, a continuum light observation, and a H-alpha observation. At Hida Observatory in Kyoto University, there is a powerful instrument observing the sun in H-alpha line and its wings called Solar Dynamics Doppler Imager (SDDI) installed on Solar Magnetic Activity Research Telescope (SMART) (Ichimoto et al, 2017).…”

Section: Prediction By H-alpha Imagementioning

confidence: 99%

Space Weather Prediction from the Ground: Case of CHAIN

Seki¹,

Ueno²,

Isobe³

et al. 2018

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In this article, we insist on the importance and the challenges of the prediction of solar eruptive phenomena including flares, coronal mass ejections (CME), and filament eruptions fully based on the ground-based telescopes. It is true that satellites' data are indispensable for the space weather prediction, but they are vulnerable to the space weather effects. Therefore, the ground-based telescopes can be complementary to them from the viewpoint of space weather prediction.From this view point, one possible new flare prediction method that makes use of H-alpha, red wings, and blue wings images obtained by the SDDI/SMART, the ground-based telescope at Hida Observatory, is presented. And in order to show the possibility for the actual operation based on that method, the recent progress of CHAIN project, the international observation network, is mentioned in terms of their outcomes and capacity buildings.

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“…Hori and Culhane (2002) studied 50 prominence eruptions observed at 17 GHz by the Nobeyama Radioheliograph (Nakajima et al 1994) and found that 92% of them were associated with CMEs. Seki et al (2019a) investigated 43 filament disappearances in H α data observed by the Solar Dynamics Doppler Imager (SDDI) (Ichimoto et al 2017) on the Solar Magnetic Activity Research Telescope (SMART) (UeNo et al 2004) at Hida Observatory, Kyoto University, and found that 50% of them were associated with CMEs. McCauley et al (2015) studied 904 filament and prominence eruptions observed in He(II) (304 Å) by the Atmospheric Imaging Assembly (AIA) (Lemen et al 2011) and found that 73% of them were associated with CMEs.…”

Section: Introductionmentioning

confidence: 99%

Relationship between three-dimensional velocity of filament eruptions and CME association

Seki

Otsuji

Ishii

et al. 2021

Earth Planets Space

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It is widely recognised that filament disappearances or eruptions are frequently associated with Coronal Mass Ejections (CMEs). Since CMEs are a major source of disturbances of the space environment surrounding the Earth, it is important to investigate these associations in detail for the better prediction of CME occurrence. However, the proportion of filament disappearances associated with CMEs is under debate. The estimates range from $$\sim$$ ∼ 10 to $$\sim$$ ∼ 90% and could be affected by the manners to select the events. In this study, we aim to reveal what parameters control the association between filament eruptions and CMEs. We analysed the relationships between CME associations and the physical parameters of filaments including their length, maximum ascending velocity, and direction of eruptions using 28 events of filament eruptions observed in H$$\alpha$$ α . We found that the product of the maximum radial velocity and the filament length is well correlated with the CME occurrence. If the product is larger than $$8.0 \times 10^{6}$$ 8.0 × 10 6 $$\text {km}^{2}$$ km 2 $$\text {s}^{-1}$$ s - 1 , the filament will become a CME with a probability of 93%, and if the product is smaller than this value, it will not become a CME with a probability of 100%. We suggest a kinetic-energy threshold above which filament eruptions are associated with CMEs. Our findings also suggest the importance of measuring the velocity vector of filament eruption in three-dimensional space for the better prediction of CME occurrence.

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A New Solar Imaging System for Observing High-Speed Eruptions: Solar Dynamics Doppler Imager (SDDI)

Cited by 44 publications

References 14 publications

Synoptic solar observations of the Solar Flare Telescope focusing on space weather

Synoptic solar observations of the Solar Flare Telescope focusing on space weather

Space Weather Prediction from the Ground: Case of CHAIN

Relationship between three-dimensional velocity of filament eruptions and CME association

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