We provide a self-contained account of the B vs. H constitutive relation ne
ar H-c1 in Type II superconductors with various types of quenched random di
sorder. The traditional Abrikosov result, B similar to [ln(H - H-c1)](-2),
valid in the absence of disorder and thermal fluctuations, changes signific
antly in the presence of disorder. Moreover, the constitutive relations wil
l depend strongly on the type of disorder. In the presence of point disorde
r, B similar to (H - H-c1)(3/2) in three-dimensional (thick) superconductor
s as shown by Nattermann and Lipowsky. In two-dimensional (thin film) super
conductors with point disorder, B similar to (H - H-c1). In the presence of
parallel columnar disorder, we find that B similar to exp[-C-3/(H - H-c1)]
in three dimensions, while B similar to exp[-C-2/(H - H-c1)(1/2)] in two d
imensions. In the presence of nearly isotropically splayed disorder, we fin
d that B similar to (H - H-c1)(3/2) in both two and three dimensions. (C) 2
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