Comparison of The Energy Spectra Between Single Shock and Converging - - PowerPoint PPT Presentation

Comparison of The Energy Spectra Between Single Shock and Converging Double-Shock

Speaker: Wang Xin

Co-authors: Yan Yihua, Ding Mingde, Wang Na, & Shan Hao

Xinjiang Astronomical Observatory, Chinese Academy of Sciences CAS Key Laboratory of Solar Activity, NAOC email: wangxin@xao.ac.cn

The 35th International Cosmic Ray Conference

Bexco, Busan, Korea 10-20,July,2017

Previous Studies Using MC Method

1, The dynamical shock structures, A&A, Wang & Yan (2011). 2, Injection rate, ApJS, Wang, et al (2013). 3, CME-driven shock, RAA, Wang & Yan (2012). 4, Emax in an Isolated shock, RAA,Wang, et al (2016) 5, Emax in two converging shocks, ApJ, Wang, et al (2017).

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Motivation

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Dec-14-2006 SEP (Mewaldt et al., 2008)

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Simulate the“Break”Using MC Method

1, Up to now, it is hardly predicted by numerical methods. ApJ, (Malkov et al., 2013). 2, Simulated Emax ∼ 4MeV, in single bow shock. ApJ, (Knerr+,1996) 3, Simulated Emax ∼ 5MeV, in single CME shock RAA, (Wang+,2012) 4, Simulated Emax ∼ 20MeV, in double converging shocks. ApJ, (Wang+,2017)

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Single Shock Model

50 100 150 200 250 300 The Schematic Diagram of the Simulation Box X (Xmax=1000Re) ICME reflective wall FEB VL V Shock U B0 Vshock |U2|>|U|>|U1| Vshock Downstream Upstream FEB VL U1=−600km s−1 U2=−1042km s−1

∆ U=442km s−1

Xfeb = 300Re Precursor Foreshock

Vth=46kms−1 τ0=13" 4

Spectra of Single Bow Shock

ApJ (Knerr+1996): Emax @ ∼3-4MeV

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Spectra of Single CME Shock

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Flux ( cm2.s.sr.MeV ) −1 Energy (MeV) The Energy Spectrum E−1.1074 Final Energy Spectrum Initial Energy Spectrum

RAA (Wang et al., 2012): Emax @ ∼5MeV

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Emax in an Isolated Shock

T0 T0/2 T0/3 T0/4 T0/5 T0/12.5 10 15 20 25 Maximum Energy Emax in Cases with Different τ The Constants of the Scattering Time τ The Maximum Energy Particles (MeV) 2.9780 3.0489 5.5506 3.7031 2.8381 3.5620 A B C D E F Shape−preserving interpolant Cases in A,B,C,D,E,F (σ=π,µ=0) shape−preserving

Emax saturation @ ∼ 5.5MeV (RAA, Wang+2016)

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Spectra in Isolated Shock

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Flux ( [ cm2.s.sr.keV ]−1 ) Energy (eV) The Energy Spectrum in Different Scattering Time A,T0 (Emax=2.9780MeV) B,T0/2 (Emax=3.0489MeV) C,T0/3 (Emax=5.5506MeV) D,T0/4 (Emax=3.7031MeV) E,T0/5 (Emax=2.8381MeV) F,T0/12.5(Emax=3.562MeV) Initial Spectrum

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Double Converging Shocks

100 200 300 400 500 600 X CME reflective wall The Schematic Diagram of the Simulation Box in Double Shocks Model Earth reflective wall Precursor2 Precursor1 Vsh1 IMF Downstream2 Downstream1 VL VL V Vsh2 VL

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U02 U01 Upstream2 Upstream1

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Velocity Profiles

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Density Profiles

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Particles Acceleration in Double Shocks

50 100 150 200 250 200 400 600 10 20 30 40 Time Particle Acceleration (Q=8) Position Velocity Vmax=37.3926

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Particles Acceleration in Double Shocks

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Protons 12/13:0200 − 12/14:2200 E−1.17±0.11 E−2.55±0.10 E−2.48±0.12 E−1.07 E−2.45 Comparison of the Energy Spectra Kinetic Energy (MeV) Protons / (cm2−sr−MeV ) Observed Spectrum Simulated Spectrum

ApJ (Wang et al., 2017): Ebr∼5MeV

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Comparison of Spectra

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Protons 12/13:0200 − 12/14:2200 E−1.17±0.11 E−2.55±0.10 E−2.48±0.12 E−1.07 E−2.45 Comparison of the Energy Spectra Kinetic Energy (MeV) Protons / (cm2−sr−MeV ) Observed Spectrum Simulated Spectrum

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Flux ( cm2.s.sr.MeV ) −1 Energy (MeV) The Energy Spectrum E−1.1074 Final Energy Spectrum Initial Energy Spectrum

Converging-Shock Model <———-> Single-Shock Model

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Summary and Conclusions

1,Find the saturation of the Emax∼ 5MeV in single shock model. Fit to the obser- vation at lower energy range. 2,Obtain the extensive energy spectral range up to Emax∼ 20MeV in double converging-shock model. 3,Identify the energy“break”Ebreak∼5MeV in double converging-shock model. 4,We suggest converging-shock interac- tion can produce the energy “break”.

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Thank For Your Attendings !

References

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