Space Environment Measurements and Applications on the Tianhe Core Module of China Space Station
doi: 10.11728/cjss2022.04.yg16
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Abstract: Tianhe Core Module of China Space Station (CSS) equips a set of instruments consisting of a Particle Fluxes and Solar Activity Detector (PFSAD) and two Atmospheric Density Multi-directional Detectors (ADMDs). The PFSAD is to measure X-rays from the Sun and energetic particles in the low-latitude and low altitude regions, including electrons, protons, and helium ions. The ADMDs are to measure thermospheric atmospheric density. The instruments provide real-time data of the orbital space environment, including solar flares, energetic particle variation and thermospheric density enhancement. All the data contribute to the CSS space weather service for mission control and astronaut’s safety. The paper gives preliminary analyses of the space environment measurements from the PFSAD and the ADMDs. By further analysis, the 1024-channel fine spectra of the solar X-ray can be used to study the mechanism of solar flares and their impacts on the Earth’s atmosphere. Data accumulation will be helpful for analyzing mid-term and long-term variations of the South Atlantic Anomaly and atmosphere density. Furthermore, the data are useful to calibrate previous empirical models and establish new models to study the space environment.
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Key words:
- Space environment /
- Tianhe core module /
- China Space Station (CSS)
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Table 1. Information of energetic particle channels of PFSAD
Protons/MeV α ion/(MeV/u) Electrons/MeV P1: 4–9 I1: 4–12.5 E1: 0.2–0.3 P2: 9–15 I2: 12.5–16.4 E2: 0.3–0.4 P3: 15–40 I3: ≥16.4 E3: 0.4–0.5 P4: 40–80 E4: 0.5–0.6 P5: 80–165 E5: 0.6–0.8 P6: ≥165 E6: 0.8–1.0 E7: 1.0–1.5 E8: 1.5–2.0 E9: ≥2.0 Table 2. Information of Solar X-ray channels of PFSAD
Channels Energy threshold/keV Main channels Main channel 1: 1.5–12.4
(Corresponding wavelength: 1–8Å)Main channel 2: 3.1–24.8
(Corresponding wavelength: 0.5–4Å)10 fine channels R1: 1.5–3.1 R2: 3.1–4.0 R3: 4.0–6.0 R4: 6.0–8.0 R5: 8.0–10.0 R6: 10.0–12.4 R7: 12.4–15.0 R8: 15.0–18.0 R9: 18.0–21.0 R10: 21.0–24.8 1024 fine channels
(solar flare mode)1.5–24.8 divided in 1024 channels Table 3. Geometric factors of various channels of different particles
Particle species Geometric factor /(cm–2·sr–1) Electrons E1 E2 E3 E4 E5 E6 E7 E8 E9 0.139 0.125 0.065 0.072 0.104 0.115 0.146 0.166 0.254 Protons P1 P2 P3 P4 P5 P6 – – – 1.587 1.117 0.969 0.740 0.857 1.022 – – – α ions I1 I2 I3 – – – – – – 1.093 0.864 0.680 – – – – – – Table 4. Peak flux of 22 X-ray flares from May 2021 to April 2022 (1–8 Å)
Number Time (UT) GOES/(W·m–2) Tianhe/(W·m–2) Absolute difference/(W·m–2) 1 22 May 2021 21:36 1.49×10–5 1.48×10–5 –1.00×10–7 2 23 May 2021 11:08 1.19×10–5 1.31×10–5 1.20×10–6 3 26 Oct. 2021 15:57 1.02×10–5 1.19×10–5 1.70×10–6 4 28 Oct. 2021 07:40 1.42×10–5 1.40×10–5 –2.00×10–7 5 28 Oct. 2021 15:34 1.00×10–4 1.02×10–4 2.00×10–6 6 29 Oct. 2021 02:42 1.56×10–5 1.77×10–5 2.10×10–6 7 17 Dec. 2021 00:51 1.29×10–5 1.50×10–5 2.10×10–6 8 14 Jan. 2022 02:03 1.84×10–5 1.92×10–5 8.00×10–7 9 20 Jan. 2022 06:01 5.51×10–5 6.50×10–5 9.90×10–6 10 29 Jan. 2022 23:32 1.14×10–5 1.04×10–5 –1.00×10–6 11 2 Mar. 2022 17:39 2.02×10–5 2.13×10–5 1.10×10–6 12 15 Mar. 2022 22:46 1.59×10–5 1.68×10–5 9.00×10–7 13 28 Mar. 2022 11:29 4.06×10–5 6.46×10–5 2.40×10–5 14 29 Mar. 2022 01:11 2.22×10–5 2.09×10–5 –1.30×10–6 15 31 Mar. 2022 18:35 9.67×10–5 1.08×10–4 1.13×10–5 16 2 Apr. 2022 02:56 2.91×10–5 3.59×10–5 6.80×10–6 17 2 Apr. 2022 13:55 3.94×10–5 4.37×10–5 4.30×10–6 18 15 Apr. 2022 11:49 2.21×10–5 1.96×10–5 –2.50×10–6 19 17 Apr. 2022 02:11 1.89×10–5 2.04×10–5 1.50×10–6 20 17 Apr. 2022 03:34 1.16×10–4 1.12×10–4 –4.00×10–6 21 18 Apr. 2022 07:48 1.36×10–5 2.23×10–5 8.70×10–6 22 18 Apr. 2022 10:27 1.19×10–5 1.30×10–5 1.10×10–6 -
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