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Physics 777 Plasma Physics and Magnetohydrodynamics (MHD) Instructor: Gregory Fleishman Lecture 11. Particle Transport 11 November 2008
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Plan of the Lecture Particle Transport in Collisionless Plasma Particle Diffusion in the Turbulent Fields Particle Trapping in Magnetic Structures Effect of Coulomb Collisions
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Section 1. Particle Transport in Collisionless Plasma Free Streaming Particle Transport Particle Diffusion in Random Fields Particle Advection Turbulent Diffusion of Charged Particles
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Section 2. Particle Diffusion in the Turbulent Fields. Propagation of CRs in the Galaxy. Credit: A. Dar & A. De R´ujula (2008)
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Now we can obtain the Green’s function G(r) for D=const Credit: M. Kachelrieß (2008)
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~ 10 7 yr >> fr.st
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Section 3. Particle Trapping in Magnetic Structures. Case of the Solar Corona. M. Aschwanden. Chapter 12
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Section 4. Particle Trapping in Magnetic Structures. Effect of Coulomb Collisions.
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=(d ln F/dt) -1 ~ ( / n ff Be f ~ f Be
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Section 5. Homework Assume free propagation of the cosmic rays (CR) across the Galactic disk (d=500 pc). Estimate the residence time of the CRs in the disk. Assume diffusive propagation of CRs at 100 GeV with diffusion coefficient D(100 GeV) =5x10 27 cm 2 /s. Estimate: a) mean free path; b) residence time in the disk; c) anisotropy (assume dipole type of anisotropy and apply Fick’s low). Find energy dependences of the above (a-c) measures for the power-law turbulence spectra with indices = 1; 1.7; 2.
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