def _magnetic_field_strength(field, data):
xm = "relative_magnetic_field_%s" % axis_names[0]
ym = "relative_magnetic_field_%s" % axis_names[1]
zm = "relative_magnetic_field_%s" % axis_names[2]
B2 = (data[ftype, xm])**2 + (data[ftype, ym])**2 + (data[ftype, zm])**2
return handle_mks_cgs(np.sqrt(B2), field.units)
def _magnetic_field_poloidal(field, data):
bm = handle_mks_cgs(
data.get_field_parameter("bulk_magnetic_field"), field.units)
r = data["index", "r"]
z = data["index", "z"]
d = np.sqrt(r * r + z * z)
rax = axis_names.find('r')
zax = axis_names.find('z')
return ((data[ftype, "magnetic_field_r"] - bm[rax]) * (r / d) +
(data[ftype, "magnetic_field_z"] - bm[zax]) * (z / d))
def _relative_vector(field, data):
iax = axis_order.index(ax)
d = handle_mks_cgs(data[field_components[iax]], field.units)
bulk = handle_mks_cgs(get_bulk(data, basename, d.unit_quantity),
field.units)
return d - bulk[iax]
def _magnetic_field_toroidal(field, data):
ax = axis_names.find('phi')
bm = handle_mks_cgs(
data.get_field_parameter("bulk_magnetic_field"), field.units)
return data[ftype, "magnetic_field_phi"] - bm[ax]