Anisotropy in theBPhase ofHe3

The magnetic anisotropy of the $B$ phase (assumed to be a Balian-Werthamer phase) is investigated within the Landau-Ginzburg theory. The anisotropy is determined by the action of the dipolar energy and the magnetic field on a single vector $\overrightarrow{\mathrm{n}}$ and it is shown that walls will induce variations in $\overrightarrow{\mathrm{n}}$ on a scale of $R_C\sim 0.1$ cm. In the presence of a field $H$ this characteristic length becomes $\frac{R_C{H}_B}{H}$, where $H_B$ is of the order of 100 Oe.