Physics – Plasma Physics
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufmsm13b2059h&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #SM13B-2059
Physics
Plasma Physics
[7867] Space Plasma Physics / Wave/Particle Interactions
Scientific paper
Recent particle simulations have successfully reproduced the generation process of whistler-mode rising-tone emissions like chorus emissions [1]. Chorus emissions are interpreted as triggered emissions by a coherent whistler-mode wave excited at a constant frequency via the linear cyclotron resonance instability driven by temperature anisotropy of energetic electrons. By injecting a triggering wave artificially from the magnetic equator, we find that triggering waves with different wave amplitudes result in rising-tone emissions with almost the same frequency sweep rate and saturation level. We find formation of an electron hole in the velocity phase space near the magnetic equator. The electron hole is asymmetric in the phase because of the frequency variation of the triggered emissions, which gives the inhomogeneity ratio S ˜ -0.4 as assumed in the nonlinear wave growth theory [2]. The depletion of resonant electrons due to formation of electron holes moves progressively toward the core part of the distribution function at higher pitch angles. At the large perpendicular velocity, we find formation of an electron island rather than an electron hole. A larger number of resonant electrons are trapped at high perpendicular velocities at some distance away from the equator. Because of the decreasing parallel velocity and the acceleration in the perpendicular direction, the resonant electrons trapped by the wave appear forming an island in the velocity phase space. The trapped electrons receive energy from the wave, while untrapped resonant electrons lose energy to the wave propagating away from the equator. The balance between the electron hole and the electron island in the velocity phase space determines the saturation of chorus emissions. [1] Hikishima, M., Y. Omura, and D. Summers (2010), Self-consistent particle simulation of whistler mode triggered emissions, J. Geophys. Res., 115, A12246, doi:10.1029/2010JA015860. [2] Omura, Y., Y. Katoh, and D. Summers (2008), Theory and simulation of the generation of whistler-mode chorus, J. Geophys. Res., 113, A04223, doi:10.1029/2007JA012622.
Hikishima Mitsuru
Omura Yuji
No associations
LandOfFree
Evolution of electromagnetic electron holes in the generation process of whistler-mode chorus emissions: A particle simulation study 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 Evolution of electromagnetic electron holes in the generation process of whistler-mode chorus emissions: A particle simulation study, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Evolution of electromagnetic electron holes in the generation process of whistler-mode chorus emissions: A particle simulation study will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1889406