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How to lock or limit a free ballistic expansion of Energetic Particles?. What could limit the free collisionless expansion?. Dominant Scenario: -Instabilities / to create the “waves (as scatterers)”; -Feedback of growing fluctuations on particles due to the particles – waves interaction;
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How to lock or limit a free ballistic expansion of Energetic Particles?
What could limit the free collisionless expansion? Dominant Scenario: -Instabilities / to create the “waves (as scatterers)”; -Feedback of growing fluctuations on particles due to the particles – waves interaction; -Non-Linear saturation of instability / build up of saturation spectrum;
Implementation of such scenario • -Instability: Velocity Anisotropy (“Cyclotron Instability” of Alfven waves); • -Feedback on particles: Quasilinear Theory of Particles/Cyclotron Waves Interaction; • -Non-Linear saturation: Strong MHD / Alfven Waves/ Turbulence;
Connection of Quasilinear Theory to KAM-Theory: From Planetary Resonances to Plasma
V x
V ADD MORE WAVES X
Width of resonance vs. Distance between resonances
much less than This limit corresponds to KAM (Kolmogoroff-Arnold-Mozer) case. KAM-Theorem : As applied to our case of Charged Particle – Wave Packet Interaction – “Particle preserves its orbit “
greater than That means - overlapping of neighboring resonances Repercussions: -”collectivization” of particles between neighboring waves; -particles moving from one resonance to another – “random walk”? And if yes -what isDiffusion Coefficient ?(in velocity space)
D= Repercussions: Quasilinear Theory, Plateau Formation, Beam + Plasma Instability Saturation etc.
General Conclusions • Kolmogoroff: Application of KAM theory to the Dynamics of Planetary System • Plasma case: Application to the Dynamics of Charged Particles more applications: • Waves-Particles interaction at Cyclotron Resonance • Magnetic Surfaces Splitting? (Trieste, 1966) • Advection in Fluids (+20 years)
Quasilinear Diffusion • . The simplified approach to such diffusion is equivalent to a truncation of quasilinear velocity space diffusion similar to tau-approximation form of collision integral in kinetic equation . Further simplifications: • -Plasma pressure is much greater than Magnetic field pressure; • -Bulk of plasma particles out of resonance with “waves” (even in strong turbulence definition); • -CR particle density too small to produce competitive nonlinear effects by themselves and do not affect waves nonlinear saturation process.
MHD + Expanding Cloud of Energetic Particles + “Return Current MHD Waves modified:
Net effect of Instabilities • Both types of Instability together: