太陽フレア中性子の生成過程 ( ≅ ガンマ線 (π 0 ) の生成過程 ≅ 高エネルギーイオンの寿命 ) さこ隆志（名大 STE 研） 基本的に R.J.Murphy, et al., ApJ Suppl,, 168, 167-194, 2007 の前半部分の review をします 1 太陽ガンマ線ミニ研究会＠名古屋大.

Presentation on theme: "太陽フレア中性子の生成過程 ( ≅ ガンマ線 (π 0 ) の生成過程 ≅ 高エネルギーイオンの寿命 ) さこ隆志（名大 STE 研） 基本的に R.J.Murphy, et al., ApJ Suppl,, 168, 167-194, 2007 の前半部分の review をします 1 太陽ガンマ線ミニ研究会＠名古屋大."— Presentation transcript:

1 太陽フレア中性子の生成過程 ( ≅ ガンマ線 (π 0 ) の生成過程 ≅ 高エネルギーイオンの寿命 ) さこ隆志（名大 STE 研） 基本的に R.J.Murphy, et al., ApJ Suppl,, 168, 167-194, 2007 の前半部分の review をします 1 太陽ガンマ線ミニ研究会＠名古屋大 学 2015/2/16

2 References と outline 1.R.J.Murphy, et al. (2007) – フレアループにトラップされたイオンの運動を追跡 し、 foot point での nuclear interaction 率（核ガンマと 中性子生成）を計算 2.Hua et al., ApJS, 140, 563-579 (2002) –nuclear interaction の cross section と kinematics はこ こを参照 3.Murphy et al., ApJS, 63, 721-748 (1987) –Hua model 中の p-p interaction はここを参照 2

3 Injection of accelerated ions (E -s, a(t), α/p ratio) B∝PδB∝Pδ Loop length (L) Solar atmosphere model (composition, density) 3

4 Neutral Particle Emission 4 Murphy et al. では中性子と核ガン マ線放射率を計算 => π 0 -> 2γ もほぼ同じでしょう

5 neutron production cross sections (ref [2]) pp 5

6 contribution to the total neutron yield (ref [2]) 統計加速（ Bessel 関数型）の場合ショック加速（べき関数型）の場合 6

7 contribution in spectrum (ref [2]) 100MeV 地上中性子観測の おおよその threshold 7

8 ここから Murphy et al. の計算結果 8

9 Injection of accelerated ions (E -s, a(t), α/p ratio) B∝PδB∝Pδ Loop length (L) Solar atmosphere model (composition, density) 9

10 Parameters determining neutral emission Cross section of gamma-ray and neutron yields 10

11 Magnetic Mirroring Charged particle in a uniform magnetic field Charged particle in a converging magnetic field (Mirroring) Mirrored particle never escapes from the loop. Charged particle with a large pitch angle (cosθ) can penetrate deep in the converging field （ loss cone ） 11

12 (Pitch Angle Scattering) PAS Pitch angle can change randomly. Λ ： mean free path required for an arbitrary initial angular distribution to relax to an isotropic distribution (energy independent) λ ： level of PAS, Λ/(L/2) λ= ∞; no scattering λ= 20; saturated 12

13 Composition α/p = 0.1 or 0.5 α/O = 50 3 He/ 4 He = 1 impulsive flare accelerated-ion abundances defined by Ramaty et al. 13

14 Solar Atmosphere Model sunspot(=default) Hybrid (Avrett/RHESSI ) 14

15 Basic Processes a(t) ; instantaneous α/p = 0.5 s=4 λ=300 δ=0.2 L = 11,500km 0.1 1.0 10.0 δ 0.0 0.2 0.45 Nuclear interaction rate time history λ ∞ 20 300 L 11,500 km 23,000 115,000 s 345345 Time (sec) （ λ=∞ ） 15

16 まとめ Murphy et al. が フレアループ内での高エネル ギーイオンの運動を追跡し、 foot point での nuclear interaction rate を計算した 簡単なループモデルで、様々な parameter をふり、 rate の time profile を計算 PAS=∞ （散乱しない場合）を除き、 rate は 100 秒程度で急激に減衰 継続的 injection がない限り、フレア中の高エネ ルギー粒子の寿命は 100 秒程度 16

17 Backup 17

18 Gamma-line yield (time integrated) Independent from the physical parameters α- αcomplex α+ He → 7 Be*, 7 Li* → 0.478, 0.429 MeVγ Power index dependence is different from line to line. -> RATIO?? ATTENTION TO NORMALIZATION 18

19 Gamma-ray yield ratio Gamma-line ratios are good estimator for the accelerated ion power index. 19

20 Gamma-ray yield ratio Gamma-line ratios are good estimator for the accelerated ion power index. 20

21 2.223 MeV/4.438MeV(C) ratio heliocentric angle dependence 21

22 Neutron Yield 22

23 Effective Energy (1) 23

24 Effective Energy (1) Spectrum must be multiplied 24

25 Effective Energy (2) 6.129 MeV O line FWHM is defined as Effective energy 25

26 Effective Energy (3) (gamma-line) 26

27 Effective Energy (4) (neutron) 27

28 Application to the June 4 1991 event From optical observation, L=11,500, 34,500 or 65,000 km (combination of the foot point) Power index,α/p ratio are obtained from O/Ne ratio and α-α complex/C ratio 28

29 Index vs. α/p ratio 99% confidence contours from 2 methods 29

30 δ- λ(physical paramters) From line Doppler shift From line time history a(t) ; instantaneous 30

31 Prompt γtime history a(t) ; instantaneous 31

32 Neutron profile Using all the parameters determined, neutron profile observed by OSSE at >23MeV is compared with model. 32

33 Neutron profile (space) Simple power law power law + cutoff @ 125MeV 33

34 Summary Self-consistent method using updated cross section is developed. Success requires measurements that cover a wide range of the observables… The method is applied for an event. Neutron observations are important for >100MeV. 34

35 additional 35

36 Neutron Yield (2) 36