HR: 08:40h
AN: SM51D-03 [Abstracts]
TI: Particle Acceleration Mediated by Magnetic Islands: Observations and Simulations
AU: * Chen, L
EM: lijen.chen@unh.edu
AF: University of New Hampshire, 39 College Rd.
EOS Space Science Center, Durham, NH 03824, United States
AU: Bhattacharjee, A
EM: amitava.bhattacharjee@unh.edu
AF: University of New Hampshire, 39 College Rd.
EOS Space Science Center, Durham, NH 03824, United States
AU: Bessho, N
EM: naoki.bessho@unh.edu
AF: University of New Hampshire, 39 College Rd.
EOS Space Science Center, Durham, NH 03824, United States
AU: Yang, H
EM: hongang.yang@unh.edu
AF: University of New Hampshire, 39 College Rd.
EOS Space Science Center, Durham, NH 03824, United States
AB:
Magnetic reconnection is the underlying process that
impulsively release an enormous amount of magnetic energy
in solar and stellar flares, and substorms in the Earth's magnetosphere.
Studies of energy release during solar flares, in particular, indicate
that up to 50 percent of the released energy is carried by accelerated
20-100 keV suprathermal electrons.
How so many electrons can gain so much energy during
reconnection has been a long-standing question. In this study (to appear
in Nature Physics 2007),
we use multi-spacecraft measurements of energetic electrons from the Earth's
magnetotail to demonstrate that the presence of energetic electrons
is linked to the dynamics of magnetic islands. Specifically, we
show that the peaks of energetic electron fluxes occur at sites of
compressed density within islands.
The strong density sub-structures within
islands suggest that the islands may have undergone coalescence,
which presents a potential new mechanism for electron
acceleration during reconnection.
We will compare these observations with Hall MHD and PIC simulations to
assess the particle acceleration efficiency of this mechanism.
DE: 2700 MAGNETOSPHERIC PHYSICS (6939)
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 7845 Particle acceleration
DE: 7846 Plasma energization
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting