THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation

Details THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation

Dec 2009

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009agufmsm44a..03l&link_type=abstract

American Geophysical Union, Fall Meeting 2009, abstract #SM44A-03

Physics

Plasma Physics

[2730] Magnetospheric Physics / Magnetosphere: Inner, [2772] Magnetospheric Physics / Plasma Waves And Instabilities, [2774] Magnetospheric Physics / Radiation Belts, [7867] Space Plasma Physics / Wave/Particle Interactions

Scientific paper

A statistical survey of plasma densities and electron distributions (0.5-100 keV) is performed using data obtained from the THEMIS spacecraft in near-equatorial orbits from 1 July 2007 to 1 May 2009 in order to investigate the optimum conditions for whistler-mode chorus excitation. The plasma density inferred from the spacecraft potential, together with in situ magnetic field is used to construct global maps of cyclotron and Landau resonant energies under weak, moderate, and strong geomagnetic activity. Statistical results show that chorus intensity increases at higher AE index, with the strongest waves confined to regions where the ratio between the plasma frequency and gyrofrequency, fpe/fce, is less than 5. On the nightside, large electron anisotropies and intense chorus emissions are confined within 8 RE. Furthermore, as injected plasma sheet electrons drift from midnight through dawn toward the noon sector, their anisotropy increases and peaks on the dayside at L > 7, in good correlation with intense chorus emissions observed in the prenoon sector. These statistical results are consistent with generation of upper-band (f > 0.5 fce) and lower-band (f < 0.5 fce) chorus through cyclotron resonant interactions with suprathermal electrons. Two typical events are studied in greater detail, and additional features are identified, such as pancake distributions below ~2 keV in the dayside outer magnetosphere, responsible for upper-band chorus, and very isotropic distributions for a few keV electrons, which could be produced by Landau resonance, and contribute to the formation of the typical gap in the chorus spectrum near 0.5 fce.

Affiliated with

Also associated with

No associations

Rating

THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation 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 THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and THEMIS Analysis of Observed Equatorial Electron Distributions Responsible for Chorus Excitation will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1880898