Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves

Details Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves

Apr 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003jgra..108.1150d&link_type=abstract

Journal of Geophysical Research (Space Physics), Volume 108, Issue A4, pp. SMP 5-1, CiteID 1150, DOI 10.1029/2002JA009650

Physics

4

Magnetospheric Physics: Mhd Waves And Instabilities, Magnetospheric Physics: Ring Current, Magnetospheric Physics: Storms And Substorms, Magnetospheric Physics: Numerical Modeling

Scientific paper

A one-dimensional linear hybrid gyrokinetic-magnetohydrodynamic δf particle in cell simulation code is developed to study the detailed mechanisms of energetic particle drift-bounce resonant destabilization of Alfvén modes in the ring-current region of the magnetosphere. The model plasma is composed of a cold (10-100eV) component which provides inertia plus a tenuous energetic (~10 keV) ``ring-current'' component which provides both resonant destabilization and compressional stabilization of MHD modes. Full kinetic effects such as finite Larmor radii and particle magnetic bounce and precessional drift motions are retained nonperturbatively. A simple finite β dipolar equilibrium model is assumed (β is the ratio between plasma and magnetic pressures). Simulations show excellent agreement with earlier perturbative analyses. Results show that when the energetic ion thermal velocity is super-Alfvénic, the ions destabilize both odd and even parity shear Alfvén MHD modes via the drift-bounce resonances. The growth rates of the resulting modes scale linearly with plasma β. The most unstable of these modes are found to be drift-bounce resonance destabilized modes with odd parity, with wave numbers such that k⊥ρ ~ 0.5 at the equator (ρ is the energetic ion Larmor radius). The destabilization typically occurs at a critical wave number k⊥ρ ~ 0.3. When the wave number is close to this critical value and the plasma β is close to the ideal MHD critical value, the mode frequency is determined by the energetic particle dynamics, similar to the energetic particle modes (EPMs) observed in laboratory fusion plasma experiments. When the energetic particles have Alfvénic or sub-Alfvénic thermal velocity, they contribute to damping of the MHD modes via the bounce resonance.

Affiliated with

Also associated with

No associations

Rating

Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves 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 Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinetic theory of geomagnetic pulsations: 4. Hybrid gyrokinetic simulation of drift-bounce resonant excitation of shear Alfvén waves will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-848986