Speaker
Rahul Kumar
(Ben Gurion University)
Description
The dynamics of two initially unmagnetized relativistic counter-streaming homogeneous ion-electron
plasma beams are simulated in two dimensions using the particle-in-cell (PIC) method. It is shown
that current laments, which form due to the Weibel instability, develop a large scale longitudinal
electric eld in the direction opposite to the current carried by the laments as predicted by theory.
This eld, which is partially inductive and partially electrostatic, is identied as the main source of
net electron acceleration, greatly exceeding that due to magnetic eld decay at later stages. The
transverse electric eld, though larger than the longitudinal one, is shown to play a smaller role in
heating electrons, contrary to previous claims. It is found that, in 1D, the electrons become strongly
magnetized and are not accelerated beyond their initial kinetic energy. Rather, the heating of the
electrons is enhanced by the bending and break-up of the laments, which releases electrons that would
otherwise be trapped within a single lament and slow the development of the Weibel instability (i.e.
the magnetic eld growth) via induction as per Lenz's law. In 2D simulations electrons are heated to
about one quarter of the initial kinetic energy of ions. The magnetic energy at maximum is about 4
percent, decaying to less than 1 percent by the end of the simulation. The ions are found to gradually
decelerate until the end of the simulation by which time they retain a residual anisotropy less than
10 percent.
| Registration number following "ICRC2015-I/" | 168 |
|---|---|
| Collaboration | -- not specified -- |
Author
Rahul Kumar
(Ben Gurion University)
