| 74 | Now, the ram pressure as a function of r from the cylinder's center is given by: |
| 75 | |
| 76 | [[latex($P_{ram} = \rho v^2(\frac{R}{r})^2$)]] |
| 77 | |
| 78 | (assuming spherical dilution of a constant radial velocity ejecta), where R is the radius of the CF cylinder. |
| 79 | |
| 80 | Balancing ram pressure and magnetic pressure at the rings inner edge gives: |
| 81 | |
| 82 | [[latex($\rho v^2(\frac{R}{r_i})^2 = B_0^2(\frac{r_0}{r_i})^2$)]] |
| 83 | |
| 84 | or |
| 85 | |
| 86 | [[latex($\boxed{r_0 = \sqrt{\beta_{ram}} R}$)]] |
| 87 | |
| 88 | which for our sims gives |
| 89 | |
| 90 | [[latex($\boxed{r_0 \approx 6R}$)]] |
| 91 | |
| 92 | Our ring has not yet reached steady state, so the outer boundary of the ring may come to rest at about 6R. What about for the inner radius of the ring? To get this we use flux-freezing, i.e., |
| 93 | |
| 94 | [[latex($\theta_1 = \theta_2$)]] |
| 95 | |
| 96 | where |
| 97 | |
| 98 | |