1. Computational Astrophysics: Magnetic Fields and Charged Particle Dynamics 8-dec-2008

2. Topics this week B&S Chapter 8 = Collisional Kinetic Theory Plasma transport coefficients Electrical conductivity Diffusion coefficient Heat conductivity Viscosity Ambipolar diffusion / ambipolar drift Two-fluid (ions & electrons) Three-fluid (neutral, ions & electrons)  Most astrophysics MHD-applications depend on this!!

3. Tasks today Read B&S Section 8.1: introduction Section 8.2: transport coefficients carefully enough to understand the derivation of expression (8.8) for the electrical conductivity more expressions of the same type; think of these as examples of the same technique, and use them to figure out how the technique works. Solve Exercise 8.1 in B&S

4. B&S Chapter 8; collisional plasmas

5. The BKG model Note that this is only a model of collisional relaxation! The ”relaxation” could (and does actually!) depend on the particle velocity

6. Definition of transport coefficients Flux of something, proportional to a gradient

7. The Maxwell distribution to use in the BKG model So, a Maxwellian distribution with density, temperature, and velocity varying with position

9. Exercises Today: Electrical conductivity 5a = Exercise 8.1 in B&S Thursday: Physical discussion of coeffs 5b = Exercise 8.2 in B&S 5c = Ambipolar diffusion, with neutrals