Plasma Leakage Through a Low-βLine Cusp

The half-width of the leakage aperture of plasma through a low-$\beta$ line cusp is found to be twice the hybrid gyroradius ${\left(r_e{r}_i\right)}^{\frac{1}{2}}$ with $r_e$ and $r_i$ as the electron and ion gyroradii. This steady-state width is shown to develop in a time less than the ion gyroperiod.