Physics
Scientific paper
Dec 2008
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008agufmsm31a1700c&link_type=abstract
American Geophysical Union, Fall Meeting 2008, abstract #SM31A-1700
Physics
2723 Magnetic Reconnection (7526, 7835), 7833 Mathematical And Numerical Techniques (0500, 3200), 7835 Magnetic Reconnection (2723, 7526), 7845 Particle Acceleration
Scientific paper
Recent in-situ observations from the Wind and Cluster spacecraft have provided detailed information regarding the energetic electron spectrum near reconnection X lines. The Wind [Oieroset et al., 2002] data showed power law spectra with the hardest spectrum and highest electron flux near the center of the diffusion region. The Cluster data found that the electron energy spectrum became harder in the downstream region [Imada et al., 2007] and found a direct correlation between the enhanced electron fluxes and density spikes and bipolar Bz signatures [Chen et al., 2008], suggesting a direct link to the presence of magnetic islands. The mechanisms for the production of relativistic electrons are investigated using 2D particle-in-cell simulations which are initiated with a 10-island configuration with and without an initial guide field. Significant energization occurs only when the number of islands is reduced to two or three with wavelength satisfying kx L < 0.2. The energization proceeds in two distinct stages. In the first stage, a small number of electrons are accelerated to relativistic energies at the X line by the inductive electric field. The second stage is associated with the final coalescence into one large island and produces a considerably larger number of relativistic electrons. With a guide field, this stage is dominated by the formation of elongated density cavities along one pair of separatrices and continued direct acceleration at the X line. Without the guide field, the direct X line acceleration becomes unimportant, and the acceleration is localized in the flux pile-up regions [Hoshino et al., 2001] and results from the curvature drift interacting with the localized inductive electric field. Thus the presence or absence of a guide field may explain the different in-situ observations. In either case, some 15-20% of the decrease in magnetic field energy is transferred to the electrons, with a few percent appearing in relativistic (> 150 keV) electrons.
Coroniti Ferdinan V.
Pritchett Philip L.
No associations
LandOfFree
Relativistic Electron Acceleration Associated with Magnetic Reconnection 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 Relativistic Electron Acceleration Associated with Magnetic Reconnection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relativistic Electron Acceleration Associated with Magnetic Reconnection will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1095380