Surface density snapshots of our inviscid gas-rich simulations, for our single-planet model (2, left) and two-planet model (3, right) cases, taken at their end time of 5000 years. Green dashed circles are at 0.5, 1, and 1.5 au. The blue dots indicate the planets’ positions. In the single-planet snapshot, note that the vortex seen in Figure 3 has completely decayed away. No comparably strong vortex was found in the two-planet simulation at any time, and the density field appears more axisymmetric than in the single-planet case.