Calibration procedures for the CHASE/HIS science data

Qiu, Ye; ShiHao, Rao,; Li, Chuan; Fang, Cheng; Ding, M. D.; Li, Zhen; Ni, Yiwei; Wang, Wenbo; Hong, Jie; Hao, Qing; Dai, Y.; Chen, Pengfei; Wan, Xiao-Sheng; Xu, Zhi; You, Wei; Yuan, Yuan; Tao, Hong-Jiang; Li, Xiansheng; He, Yukun; Liu, Qiang

doi:10.1007/s11433-022-1900-5

Cited by 35 publications

(28 citation statements)

References 25 publications

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“…The flare was also observed in its decay phase by the Hα Imaging Spectrograph (HIS) on board the Chinese Hα So-lar Explorer (CHASE; Li et al 2022a). The CHASE/HIS 1 provides Hα spectroscopic observations with a pixel spectral resolution of 0.024 Å and a time cadence of one minute (Qiu et al 2022).…”

Section: Discussionmentioning

confidence: 99%

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

Zhang

et al. 2022

ApJL

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In this Letter, we perform a detailed analysis of the M5.5 class eruptive flare occurring in active region 12,929 on 2022 January 20. The eruption of a hot channel generates a fast coronal mass ejection (CME) and a dome-shaped extreme-ultraviolet (EUV) wave at speeds of 740–860 km s−1. The CME is associated with a type II radio burst, implying that the EUV wave is a fast-mode shock wave. During the impulsive phase, the flare shows quasi-periodic pulsations (QPPs) in EUV, hard X-ray, and radio wavelengths. The periods of QPPs range from 18 to 113 s, indicating that flare energy is released and nonthermal electrons are accelerated intermittently with multiple timescales. The interaction between the EUV wave and low-lying adjacent coronal loops (ACLs) results in contraction, expansion, and transverse vertical oscillation of ACLs. The speed of contraction in 171, 193, and 211 Å is higher than that in 304 Å. The periods of oscillation are 253 s and 275 s in 304 Å and 171 Å, respectively. A new scenario is proposed to explain the interaction. The equation that interprets the contraction and oscillation of the overlying coronal loops above a flare core can also interpret the expansion and oscillation of ACLs, suggesting that the two phenomena are the same in essence.

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Section: Discussionmentioning

confidence: 99%

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

Zhang

et al. 2022

ApJL

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“…As shown in Qiu et al (2022), the enhancement of the observed line center is mainly due to the contamination of stray light (Fig. 2).…”

Section: Observations and Data Reductionmentioning

confidence: 60%

“…The Chinese Hα Solar Explorer (CHASE, Li et al 2019Li et al , 2022) is a space-based telescope that can perform spectroscopic observations of the full solar disk in the Hα waveband. The absorptive Si i 6560.58 Å line clearly stands out in the sample spectra (Qiu et al 2022), without any distortion or disturbance from the earth atmosphere, which makes it feasible to study this line.…”

Section: Introductionmentioning

confidence: 95%

Statistical analysis of the Si I 6560.58 Å line observed by CHASE

Hong

Qiu

Hao

et al. 2022

A&A

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Context. The Si i 6560.58 Å line in the Hα blue wing is blended with a telluric absorption line from water vapor in ground-based observations. Recent observations with the space-based telescope CHASE provide a new window to study this line. Aims. We aim to study the Si i line statistically and to explore possible diagnostics. Methods. We select three scannings in the CHASE observations, and measure the equivalent width (EW) and the full width at half maximum (FWHM) for each pixel on the solar disk. We then calculate the theoretical EW and FWHM from the VALC model. An active region is also studied in particular for difference in the quiet Sun and the sunspots.Results. The Si i line is formed at the bottom of the photosphere. The EW of this line increases from the disk center to µ = 0.2, and then decreases toward the solar limb, while the FWHM shows a monotonically increasing trend. Theoretically predicted EW agrees well with observations, while the predicted FWHM is far smaller due to the absence of unresolved turbulence in models. The macroturbulent velocity is estimated to be 2.80 km s −1 at the disk center, and increases to 3.52 km s −1 at µ = 0.2. We do not find any response to flare heating in current observations. Doppler shifts and line widths of the Si i 6560.58 Å and Fe i 6569.21 Å lines can be used to study the mass flows and turbulence of the different photospheric layers. The Si i line has good potentials to diagnose the dynamics and energy transport in the photosphere.

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“…The embedded panel shows the offsets of two successive images over 100 s. The solar images are calibrated by corrections of dark-field, flat-field, and transformation of coordinates. The detailed calibration procedures are described in an accompanying paper [20]. The centroids of solar images are derived by using edge detection based on the Hough transformation [21].…”

Section: Resultsmentioning

confidence: 99%

Levitated-body ultra-high pointing accuracy and stability satellite platform of the CHASE mission

Zhang

Cheng

You

et al. 2022

Sci. China Phys. Mech. Astron.

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The CHASE satellite is designed based on the novel ultra-high pointing accuracy and stability levitated-body satellite platform, which breaks the traditional idea of rigidly connecting the satellite platform and payload. When operating in orbit, the platform and payload are non-connected and spatially levitated. By separately arranging the "noisy" and "quiet" devices, the complicated influence of platform vibration on the payload pointing direction is effectively avoided. Using the novel master-slave collaborative control method, the pointing accuracy and stability of the payload are improved considerably. In this paper, the basic principles, overall scheme, control method, and engineering implementation of a levitated-body satellite platform are discussed. Combined with the CHASE mission in-orbit data, the actual attitude pointing precision and stability of a levitated-body satellite platform are analyzed and evaluated.

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Calibration procedures for the CHASE/HIS science data

Cited by 35 publications

References 25 publications

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

Statistical analysis of the Si I 6560.58 Å line observed by CHASE

Levitated-body ultra-high pointing accuracy and stability satellite platform of the CHASE mission

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Calibration procedures for the CHASE/HIS science data

Cited by 35 publications

References 25 publications

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

First Detection of Transverse Vertical Oscillation during the Expansion of Coronal Loops

Statistical analysis of the Si I 6560.58 Å line observed by CHASE

Levitated-body ultra-high pointing accuracy and stability satellite platform of the CHASE mission

Contact Info

Product

Resources

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Statistical analysis of the Si I 6560.58 Å line observed by CHASE