Download presentation

Presentation is loading. Please wait.

Published byAri Gadsden Modified over 2 years ago

1
粒子シミュレーションで観る粒子加速 : 衝撃波、リコネクション、降着円盤 星野 真弘

2
Nonthermal Universe Cosmic Rays ACRs [Stone et al., 2008] Where and How are non-thermal particles produced? [Lin et al., 2003] Solar Flares [Nagano & Watson, 2000]

3
Supernova Remnant Shock SN1006 (Chandra) shock width ＝ electron gyro-radius of 10 TeV Bamba et al. (2002) 3 Bamba+ 2003Warren+ 2005 Tycho’s SNRSN1006 Shock downstreamupstream

4
Electron Energy Spectrum at SNR Shocks SN1006, Chandra X-ray, Long et al. 2003 Bamba et al. 2003; Long et al. 2003 upstreamdownstream V1V1 V 2 = V 1 /4 Fermi Acceleration Model shock front

5
Shock Numerical Experiment ｘ ｙ ｚ BｚBｚ EｙEｙ p +,e - injection reflection Particle-in-Cell (PIC) Simulation Modeling on Collisionless Shock 10 8-9 particles wall 5 particles fields

6
Magnetic Bubbles in High Mach Number Shock Ion-Ion streaming Instability in Hot Electrons (Wu et al. 1984) large B field with B/B 1 >15 & V a / ci scale X/(V 1 / ci ) Ma=137, pe / ce =140, mi/me=100 Shimada, MH & Amano,PoP 2010

7
Magnetic Bubbles in High Mach Number Shock Kato and Takabe, 2010 Ma=100, pe / ce =71, mi/me=30 Ion-ion Weibel with V a / ci scale Reconnection in 3D

8
Magnetic Reconnection Solar & Stellar Flare, Magnetosphere, Accretion Disks, Pulsar Wind-Nebula, Astrophysical Jets,…. Plasma Heating & Nonthermal Particle Acceleration

9
Reconnection around Heliopause Boundary Heliospheric Current Sheet Anomalous Cosmic Ray by Reconnection (Drake+ 2010) Termination shock in Heliosphere

10
Gamma Ray Flares from Crab Nebula Pulsar Magnetosphere & Wind Reconnection Model: Coroniti ApJ 1990, Kirk+ PRL 2003, Zenitani & MH PRL 2005, Jaroschek & MH PRL 2009,... Crab Nebula Tavani+, Science, 2011, Abdo+, Science, 2011

11
2D PIC Simulation Particle Trajectories, Magnetic Field Lines Particle Energies

12
Stochastic particle acceleration in multiple magnetic islands during reconnection MH, PRL (2012)

13
2 nd order Acceleration Fermi, Phys. Rev. (1949) 1 st order Acceleration MH, PRL (2012) Fermi acceleration in magnetic islands

14
Plasma processes in Accretion Disk Courtesy of Kato Magneto-Rotational Instability (MRI) Velikov 1958, Chandrasekhar 1961, Balbus & Hawly 1991,…. Matsumoto & Tajima 1995,…Sano and Inutsuka 2001,….

15
Magneto-Rotational Instability (MRI) Balbus and Hawley, 1998weak magnetic field (β>>1) β = 1-10 dynamo process MHD simulation B-lines

16
Collisionless Accretion Disk? Kinetic Magneto-Rotational Instability (MRI) and particle acceleration is important – Massive black hole (Sgr A*) – Radiatively Inefficient Accretion Flow (RIAF) – Accretion rate much smaller than the Bondi rate of 10 - 5 M * /yr net accretion rate 10 -8 M * /yr – thermal and nonthermal electrons (X-ray flare by observed Chandra & XMM-Newton), power law index p ~ 1.3 < 2

17
“Collisionless” MRI MHD + CGL + Landau Fluid Approx. (Hammett+, PoP, 1992; Quataert+, ApJ, 2002; Sharma+, ApJ, 2006) Heat Flux q in Fourier space

18
1.0 1.1 1.2 0 45 90 0 0.8 Im( )/ tan -1 (k r /k z ) MRI Mirror Mode z r B Kepler Disk MRI in anisotropic pressure

19
1.0 1.1 1.2 0 45 90 0 0.8 Im( )/ tan -1 (k r /k z ) Im( )/ 0 1 2 0 45 90 1 4 7 MRI Mirror Mode without Heat Flux with Heat Flux tan -1 (k r /k z )

20
β=100, Kepler rotation Ω 256x256x256 grids 40 particles/cell, periodic shearing box, electron-positron plasma MRI and Reconnection in PIC simulation B green: magnetic field lines color contour: angular velocity

21
Local rotating system with

22
color contour: angular velocity green: B-lines

23
E -2/3

24
2D-PIC simulation Kepler rotation Ω, Ω/ Ω c =0.1, β=1400, 300x300 grids 100 particles/cell, periodic box in meridian plane, electron-positron plasma B R Z

26
2D-PIC simulation Kepler rotation Ω, Ω/ Ω c =0.1, β=1400, 300x300 grids 100 particles/cell, periodic box in meridian plane, electron-positron plasma B R Y

28
2D-PIC simulation Kepler rotation Ω, Ω/ Ω c =0.1, gyro-radius V i / Ω c =1.7x10 2 at t=0 β=20000, 200x200 grids 8000 particles/cell, periodic box in meridian plane, electron-positron plasma B R Z

30
Onset of Reconnection Laval and Pellat (1968), Chen and Palmadesso (1984) Before Reconnection After onset of Reconnection Growth rate of tearing mode is enhanced for T ⊥ > T // Density T ⊥ /T // T ⊥ > T // T ⊥ ～ T //

32
high energetic particles (γ>20) are located outside magnetic islands middle energetic particles (γ>5) are located at outer edge of islands thermal plasma is confined inside magnetic islands E -4/3 void

33
Summary Shocks Injection/Turbulent Reconnection/Kinetic MRI – High Mach number shocks with magnetic bubbles – Particle acceleration by multiple magnetic island reconnection in a large scale system – Onset of reconnection by T ⊥ > T // during MRI evolution – Hard energy spectrum with N(E) ∝ E -1 (in 2d & 3d PIC simulations) 公開粒子コード： Astro-pCANS http://www.astro.phys.s.chiba-u.ac.jp/pcans/

Similar presentations

OK

General Relativistic MHD Simulations of Black Hole Accretion Disks John F. Hawley University of Virginia Presented at the Astrophysical Fluid Dynamics.

General Relativistic MHD Simulations of Black Hole Accretion Disks John F. Hawley University of Virginia Presented at the Astrophysical Fluid Dynamics.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on natural resources for class 9 download Ppt on population census 2011 india Ppt on central limit theorem for dummies Ppt on review of literature apa Ppt on event driven programming code Ppt on primary and secondary market Ppt on producers consumers and decomposers clip Ppt on 2d viewing pipeline Ppt on hydrostatic forces on submerged surfaces Ppt on world diabetes day