Þ dA = R2sin q dq dj = surface
element at magnetic co-latitude q
Þ rw = total surface reflectivity for incident
unpolarized radiation
Þ aw = (1 - rw)
= absorption coefficient
Þ jw = awBw (T) = emissivity (Kirchoff¹s law)
Brinkmann 1980
Anisotropy of the medium
response properties
Þ rw strongly depends on the direction of the refracted
ray
€ Pure vacuum
outside the star (neglect vacuum birefringence)
€ EM wave incident at the surface with
(E,k) is partly reflected (E¹,k¹) and partly refracted
€ Birefringence of the medium: the
refracted wave is sum on an ordinary (E¹¹1,k¹¹1)
and an extraordinary (E¹¹2,k¹¹2)
mode.
l ij = k¹i
k¹j - |k|2dij +(w2/c2)eij = Maxwell tensor
| l ij | = 0 = dispersion relation Þ refractive
index nm , m=1,2
rg » 390 A5/2 T5/2 exp(-QS/T) g cm-3 :
ion density of the condensed phase near zero pressure (Lai, 2001)
Þ plasma frequency