Physics – Plasma Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufmsh53b2036l&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #SH53B-2036
Physics
Plasma Physics
[7807] Space Plasma Physics / Charged Particle Motion And Acceleration, [7836] Space Plasma Physics / Mhd Waves And Instabilities, [7845] Space Plasma Physics / Particle Acceleration, [7863] Space Plasma Physics / Turbulence
Scientific paper
The solar wind exhibits sustained heating after escaping the solar corona, and it is anticipated that the damping of turbulent plasma modes contributes to this heating. To investigate this, we simulate the interaction of charged test particles with fully dynamical simulations of magnetohydrodynamic Alfvenic turbulence, in which particles may be accelerated by the cyclotron resonance with Alfven modes (providing perpendicular acceleration) or transit-time damping with compressive modes via the μ ∇ B force (parallel acceleration). We implement a novel time-correlated driving scheme for the turbulence, which allows us to calculate heating rates over long times for initially thermal distributions of high-gyrofrequency particles, and investigate whether energy gain is primarily thermal or non-thermal. Additionally, we calculate particle diffusion coefficients. Some agreement is found with prior theories of turbulent acceleration, but discrepancies remain. Specifically, we find that: 1) the heating rate of thermal distributions with vth >> vAlfven, where vth is the typical speed of the Maxwellian, is proportional to vth-1, implying that protons in the solar wind are heated much more effectively than electrons by turbulence above the proton gyroscale, and that minor ions are heated more effectively still; 2) thermal distributions heated by transit-time damping (TTD) develop only weak non-thermal tails, which are still exponential rather than power-law; 3) D∥ , the parallel momentum diffusion coefficient, is proportional to v⊥4, consistent with parallel acceleration of particles via TTD, for high-v⊥ particles (surprisingly, for lower v⊥, D∥ approaches a constant); 4) the resonances predicted by quasi-linear theory are observed to be highly broadened.
Lynn Jacob
Parrish Ian J.
Quataert Eliot
No associations
LandOfFree
Heating and Diffusion of Test Particles in Alfvenic Turbulence does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Heating and Diffusion of Test Particles in Alfvenic Turbulence, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Heating and Diffusion of Test Particles in Alfvenic Turbulence will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1889028