BOX MULTIPLIER - Theory Group

BOX_MULTIPLIER

Factor to ultimately determine the radial box length, as a multiple of the distance between reference singular surfaces.

Doubling this parameter doubles the box length.
To specify the box size directly when RADIAL_PROFILE_METHOD /= 3, set BOX_MULTIPLIER=-1.0 and use L_X and L_Y.
The mechanism for computing box length is perhaps one of the most puzzling aspects of running GYRO.
The formula used to compute the box length (if S_GRID=0.0) is

$\frac{L_x}{a} =$ BOX_MULTIPLIER $\times \frac{r_0}{n_{\rm ref} \, q_0 \, s_0}$

$r_0 = \,\!$ RADIUS

$n_{\rm ref} = \,\!$ TOROIDAL_REFERENCE

$q_0 = \,\!$ SAFETY_FACTOR

$s_0 = \,\!$ SHEAR

If S_GRID is nonzero, then $s_0 = \,\!$ S_GRID.
For linear runs with a single toroidal mode, set BOX_MULTIPLIER=1.0.
For nonlinear runs with many toroidal modes, increase BOX_MULTIPLIER until the desired box size is achieved.

box_multiplier

1.0