PLUTO Test Problems
4.4-patch2
|
Reconnection test (Harris sheet) in 2D. More...
Functions | |
void | InitDomain (Data *d, Grid *grid) |
In this setup - see also Section 5.3 of Mignone et al., ApJS (2012) 198:7 - we reproduce a 2D Harris current sheet with magnetic field profile given by
where l
is the half thickness of the layer. The density profile is given by
We use and
, following the guidelines of Birn et al., 2001, while
l
is user supplied.
In order to achieve equilibrium with the magnetic pressure, the thermal pressure is chosen to be , where
. The initial equilibrium is pertubed by an additional magnetic field defined as
The Lundquist number of a plasma is defined as
where is the Alfvén velocity,
,
is a typical lenght scale, and
the plasma resistivity. The reconnection rate
, with
and
the plasma inflow and outflow velocities, follows the Sweet-Parker scaling law
. In this example several values of the resitivity
, that correspond to different values of the Lundquist number
, are provided. The reconnection rate, calculated as the ratio
(see Mignone et al., 2012) verifies the Sweet-Parker scaling in the range
(see the first figure below).
The input parameters (read from pluto.ini
) for this test problem are:
g_inputParam[ETA]
: sets the value of resistivity g_inputParam[WIDTH]
: sets the layer width l
; g_inputParam[PSI0]
: sets the amplitude of perturbation Reference