Figure 3

Phase plot and trajectories (blue line: \(\pmb{x(t)}\) , black line: \(\pmb{y(t)}\) ) for the VOFVDPM with \(\pmb{q_{1}(t)=1-4t/3{,}000, q_{2}(t)=0.6+4t/3{,}000}\) , \(\pmb{a=0}\) , \(\pmb{\mu=2.5}\) , and \(\pmb{(x(0),y(0))=(1.3,1.2)}\) .