| |
 |
| Paper: |
High Lundquist Number Resistive MHD Simulations of Magnetic Reconnection: Searching for Secondary Island Formation |
| Volume: |
444, 5th International Conference of Numerical Modeling of Space Plasma Flows (ASTRONUM 2010) |
| Page: |
124 |
| Authors: |
Ng, C. S.; Ragunathan, S. |
| Abstract: |
Recently, secondary island formation due to the tearing instability of the Sweet-Parker current sheet
was identified as a possible mechanism that can lead to fast reconnection
(less sensitive dependence on Lundquist number S) both in numerical simulations using
Particle-in-Cell (PIC) method [Daughton et al. 2009], as well as using resistive
magnetohydrodynamics (MHD) [Lapenta 2008; Bhattacharjee et al. 2009].
This instability is thought to appear when S is greater than a certain threshold.
These recent results prompt us to perform more resistive MHD simulations of a basic
reconnection configuration based on the island coalescence instability,
using much higher resolutions and larger S.
Our simulations are based on a fairly standard pseudo spectral code,
which has been tested for accuracy, convergence, and compared
well with codes using other methods [Ng et al. 2008].
In our simulations, formation of plasmoids were not found,
except when insufficient resolution was used,
or when a small amount of noise was added externally.
The reconnection rate is found to follow the Sweet-Parker scaling when no noise is added,
but increases to a level independent of S with noise,
when plasmoids form.
Latest results with S up to 2×105 will be presented. |
|
|
|
|
|
