輔仁大學 太空物理 ( Space Physics )

1. 第一章 太陽 Chapter 1 The Sun 輔仁大學 太空物理(Space Physics)

2. 大綱 • 第1.1節 結構與能量 • 內部構造與能量傳播 • 第1.2節太陽輻射 • 太陽光與太陽風 • 太陽風暴

3. 太空是什麼

5. Bow Shock 1977年 Termination Shock Heliopause Voysger 1 & 2 http://voyager.jpl.nasa.gov/ Heliosphere

6. 大氣—地球表面至地表80公里 • 太空—地球表面50公里到太陽系(太陽風終極震波) • 天文—太陽、恆星、星系以至銀河 • 科學—數學、生物、物理、化學與自然科學 • 科技—電機、機械、土木…等工業技術 太空環境 太空科學 太空旅行 太空科技

7. 更新：航海家1,2已接近日磁層頂

8. 太空能量的源頭

11. 太陽的基本資料 • 年齡：快50億歲了 • 體重：3.3×105個地球重 • 大小：100個地球半徑 • 密度：1.4 g/cm3 • 重力：2.7 ×102 m/s2 • 自轉週期：平均為27天 • 地球重：5.97×1027Kg • 地球半徑：6400 Km

13. 核 心: 能量的來源(核融合) • 0.3R⊙, 1.5×107K • 輻射層: 先吸收再以輻射傳遞 • 0.5R⊙ , 5.0×105K • 對流層: 利用對流方式傳遞 • 0.2R⊙ , 6.6×105K • 光球層: 肉眼所看到的部份 • 0.001R⊙ , 5750K • 彩球層: 最薄的一層 • 10000KM , 4500-500000K • 日 冕: 相當於太陽的大氣層 • >R⊙ ,1.5×106K

14. The source of the Sun’s energy is nuclear fusion Proton-proton cycle, four protons merges to one α-particle, the mass difference between the four protons and the α-particle corresponds to an energy of 4.3*10-12J or 26.2 MeV. The first step: Two protons merge to a deuteron, emitting a positron and a neutrino. The second step: A proton collides and merges with the deuteron, forming a 3He-nuclei under emission of a γ-quant. The third step: Two 3He-nuclei collide, they merge to an α-particle, emitting two protons and a γ-quant . The time scale of the proton-proton cycle basically is by the first step, half of the hydrogen initially present is converted into deuteron within 1010 year. Although a photon travels with the speed of light, it needs about 100000 years to diffuse from the Sun’s core to its surface.

15. Wiki

17. 不同波段下的太陽 EIT195 EIT284 EIT304 1.5 million 2 million 80,000 MDI EIT171 6000 1million

18. The Sun’s composition: hydrogen 92% in terms of particle number or 72% in terms of mass helium8% oxygen 0.06% carbon 0.03% the rest<0.01%. The Sun radiates as a black body at about 6000 K. The flux of visible solar energy varies very little and, however, the emissions at shorter wavelengths, the EUV and X-ray, vary by orders of magnitude depending on sunspot number and solar activity. Differential rotation

22. Sunspot characteristics: (i) Low temperature: 3900°K (ii) Intense magnetic field: 200gauss (iii) Pair (iv) Cycle~11.25 years Wolf Sunspot number (Solar activity index, SSN,R) Wolf number: R=k(10*g+f) f: number of individual spot g: number of group k: comparison constant ~1 Solar min R~0 Solar max R~200 R12: 將12個月所觀測到的R值(太陽黑子數)相加起來除以12 R12=(0.5R-6 +R-5 +R-4 +R-3 +R-2 +R-1 +R0+R1+R2+R3+R4+R5 +0.5R6)/12

23. The 1st cycle: 1755~1766 Now: 24th cycle, 2008.01.04 ~ The Maunder Minimum: 1645~1715

24. 不同波段的太陽黑子

25. 近距離觀測太陽黑子

28. 太陽的自轉—差動式自轉

30. 太陽光與太陽風

34. 太陽光譜

35. The solar wind The solar wind is a continuous flow of charged particle. Slow solar wind 250-400 km/s, 8ions/cm3 at 1AU, Streamer belt Strongly overexpending flux tubes. Fast solar wind 400-800 km/s, 3ions/cm3 at 1AU, Coronal hole

37. 太陽活動強度不同之差異

39. tanθ=rω/Vsw

42. 太 陽 風 暴

44. Solar index, F10.7: 以太陽表面所輻射出來之波長為10.7cm(2800MHz)的電磁波強度作為太陽活動強弱的參考。下圖為F10.7與太陽黑子數的比較。

45. The active Sun • Flare • A flare is a burst of “light” (easily observed at red Hα 6563A) occurring in the chromosphere near a sunspot. Life time 3 min up to 2 hr. • Hα-flares are ranked in the size (importance, 1-4) and brilliance (f, n, b). • X-ray flares are classified by power flux level of 1-8A (C, M, X). • Radio burst • Radio bursts are generally associated with flares and originate from all levels of the solar atmosphere.

46. X-RAY FLARE的強度區分如下表所示：