Physics 777
Plasma Physics and
Magnetohydrodynamics (MHD)
Instructor: Gregory Fleishman
Lecture 10. Wave-Particle Interactions
4 November 2008
Plan of the Lecture
• Basic Consideration; Conservation Laws
• Quasi-Linear Approximation
• Saturation of Instabilities due to WaveParticle Interactions
• Non-Resonant Wave-Particle Interactions
Section 1. Basic Consideration; Conservation Laws
Section 2. Quasi-Linear Approximation
Credit: E.Kontar
Section 3. Saturation of
Instabilities due to WaveParticle Interactions
Analytical treatment is possible under a number of simplifications
Time profiles of
solar radio spikes
Hamilton & Petrosian 1992
Section 4. Non-resonant wave-particle interactions
• Diffusion in small-scale turbulence
• Weak long-wavelength turbulence
• Strong long-wavelength turbulence
Section 5. Homework
• Using Hamilton & Petrosian (1992)
expressions for mean free path (l) and
angular diffusion coefficient, calculate what
spectrum of whistler turbulence is needed to
ensure l is equal to Larmour radius.
• What spectrum of whistler turbulence is
needed to ensure that the escape time (Eq.
10) does not depend on particle energy: a)
in non-relativistic case, b) in relativistic
case.