| 137 | The Hall frequency is given by $\omega_H=\frac{e B}{m_i c}$ and the corresponding length scale $L_H = \frac{v_{A}}{\omega_H}$ |
| 138 | |
| 139 | |
| 140 | Comparing the advective and the Hall terms, we can calculate the length scale for magnetic gradients below which the Hall term becomes larger than the advective term. |
| 141 | |
| 142 | $L = \frac{B}{n e v}$ |
| 143 | |
| 144 | For the lab experiments, $B = 5 T$, $v = 60 \mbox{km/s}$, $n=1\times 10^{18} \mbox{cm}^{-3}$ which works out to give |
| 145 | |
| 146 | $L = \frac{5\times 10^4 G}{\sqrt{4\pi} \left ( 1\times 10^{18}\right) \left( 6 \times 10^6 \right) \left ( 5.67956774 \times 10^{-20} \right )} \frac{\mbox{g}^{1/2} \mbox{cm}^{-1/2} \mbox{s}^{-1}}{\mbox{cm}^{-3} \mbox{cm}^1 \mbox{s}^{-1} \mbox{g}^{1/2} \mbox{cm}^{1/2} } = .04 \mbox{cm}$ |
| 147 | |
| 148 | |
| 149 | |